[ACPI] Add "ec_polling" boot option

EC burst mode benefits many machines, some of
them significantly.  However, our current
implementation fails on some machines such
as Rafael's Asus L5D.

This patch restores the alternative EC polling code,
which can be enabled at boot time via "ec_polling"

http://bugzilla.kernel.org/show_bug.cgi?id=4665

Signed-off-by: Luming Yu <luming.yu@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 722 insertions, 171 deletions

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index fca4140a50a9..2dadb7f63269 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -59,76 +59,185 @@ ACPI_MODULE_NAME		("acpi_ec")
 #define ACPI_EC_DELAY           50      /* Wait 50ms max. during EC ops */
 #define ACPI_EC_UDELAY_GLK      1000    /* Wait 1ms max. to get global lock */
 
+#define ACPI_EC_UDELAY         100     /* Poll @ 100us increments */
+#define ACPI_EC_UDELAY_COUNT   1000    /* Wait 10ms max. during EC ops */
+
 #define ACPI_EC_COMMAND_READ    0x80
 #define ACPI_EC_COMMAND_WRITE   0x81
 #define ACPI_EC_BURST_ENABLE    0x82
 #define ACPI_EC_BURST_DISABLE   0x83
 #define ACPI_EC_COMMAND_QUERY   0x84
 
-static int acpi_ec_add (struct acpi_device *device);
+#define EC_POLLING              0xFF
+#define EC_BURST                0x00
+
+
 static int acpi_ec_remove (struct acpi_device *device, int type);
 static int acpi_ec_start (struct acpi_device *device);
 static int acpi_ec_stop (struct acpi_device *device, int type);
+static int acpi_ec_burst_add ( struct acpi_device *device);
 
 static struct acpi_driver acpi_ec_driver = {
         .name =         ACPI_EC_DRIVER_NAME,
         .class =        ACPI_EC_CLASS,
         .ids =          ACPI_EC_HID,
         .ops =          {
-                                .add =          acpi_ec_add,
+                                .add =          acpi_ec_burst_add,
                                 .remove =       acpi_ec_remove,
                                 .start =        acpi_ec_start,
                                 .stop =         acpi_ec_stop,
                         },
 };
-
-struct acpi_ec {
-        acpi_handle                     handle;
-        unsigned long                   uid;
-        unsigned long                   gpe_bit;
-        struct acpi_generic_address     status_addr;
-        struct acpi_generic_address     command_addr;
-        struct acpi_generic_address     data_addr;
-        unsigned long                   global_lock;
-        unsigned int                    expect_event;
-        atomic_t                        leaving_burst; /* 0 : No, 1 : Yes, 2: abort*/
-        atomic_t                        pending_gpe;
-        struct semaphore                sem;
-        wait_queue_head_t               wait;
+union acpi_ec {
+        struct {
+                u32                             mode;
+                acpi_handle                     handle;
+                unsigned long                   uid;
+                unsigned long                   gpe_bit;
+                struct acpi_generic_address     status_addr;
+                struct acpi_generic_address     command_addr;
+                struct acpi_generic_address     data_addr;
+                unsigned long                   global_lock;
+        } common;
+
+        struct {
+                u32                             mode;
+                acpi_handle                     handle;
+                unsigned long                   uid;
+                unsigned long                   gpe_bit;
+                struct acpi_generic_address     status_addr;
+                struct acpi_generic_address     command_addr;
+                struct acpi_generic_address     data_addr;
+                unsigned long                   global_lock;
+                unsigned int                    expect_event;
+                atomic_t                        leaving_burst; /* 0 : No, 1 : Yes, 2: abort*/
+                atomic_t                        pending_gpe;
+                struct semaphore                sem;
+                wait_queue_head_t               wait;
+        }burst;
+
+        struct {
+                u32                             mode;
+                acpi_handle                     handle;
+                unsigned long                   uid;
+                unsigned long                   gpe_bit;
+                struct acpi_generic_address     status_addr;
+                struct acpi_generic_address     command_addr;
+                struct acpi_generic_address     data_addr;
+                unsigned long                   global_lock;
+                spinlock_t                      lock;
+        }polling;
 };
 
+static int acpi_ec_polling_wait ( union acpi_ec *ec, u8 event); 
+static int acpi_ec_burst_wait(union acpi_ec *ec, unsigned int event);
+static int acpi_ec_polling_read ( union acpi_ec *ec, u8 address, u32 *data);
+static int acpi_ec_burst_read( union acpi_ec *ec, u8 address, u32 *data);
+static int acpi_ec_polling_write ( union acpi_ec *ec, u8 address, u8 data);
+static int acpi_ec_burst_write ( union acpi_ec *ec, u8 address, u8 data);
+static int acpi_ec_polling_query ( union acpi_ec *ec, u32 *data);
+static int acpi_ec_burst_query ( union acpi_ec *ec, u32 *data);
+static void acpi_ec_gpe_polling_query ( void *ec_cxt);
+static void acpi_ec_gpe_burst_query ( void *ec_cxt);
+static u32 acpi_ec_gpe_polling_handler ( void *data);
+static u32 acpi_ec_gpe_burst_handler ( void *data);
+static acpi_status __init
+acpi_fake_ecdt_polling_callback (
+        acpi_handle     handle,
+        u32             Level,
+        void            *context,
+        void            **retval);
+
+static acpi_status __init
+acpi_fake_ecdt_burst_callback (
+        acpi_handle     handle,
+        u32             Level,
+        void            *context,
+        void            **retval);
+
+static int __init
+acpi_ec_polling_get_real_ecdt(void);
+static int __init
+acpi_ec_burst_get_real_ecdt(void);
 /* If we find an EC via the ECDT, we need to keep a ptr to its context */
-static struct acpi_ec   *ec_ecdt;
+static union acpi_ec    *ec_ecdt;
 
 /* External interfaces use first EC only, so remember */
 static struct acpi_device *first_ec;
+static int acpi_ec_polling_mode;
 
 /* --------------------------------------------------------------------------
                              Transaction Management
    -------------------------------------------------------------------------- */
 
-static inline u32 acpi_ec_read_status(struct acpi_ec *ec)
+static inline u32 acpi_ec_read_status(union acpi_ec *ec)
 {
         u32     status = 0;
 
-        acpi_hw_low_level_read(8, &status, &ec->status_addr);
+        acpi_hw_low_level_read(8, &status, &ec->common.status_addr);
         return status;
 }
 
-static int acpi_ec_wait(struct acpi_ec *ec, unsigned int event)
+static int
+acpi_ec_wait (
+        union acpi_ec           *ec,
+        u8                      event)
+{
+        if (acpi_ec_polling_mode) 
+                return acpi_ec_polling_wait (ec, event);
+        else
+                return acpi_ec_burst_wait (ec, event);
+}
+
+static int
+acpi_ec_polling_wait (
+        union acpi_ec           *ec,
+        u8                      event)
+{
+        u32                     acpi_ec_status = 0;
+        u32                     i = ACPI_EC_UDELAY_COUNT;
+
+        if (!ec)
+                return -EINVAL;
+
+        /* Poll the EC status register waiting for the event to occur. */
+        switch (event) {
+        case ACPI_EC_EVENT_OBF:
+                do {
+                        acpi_hw_low_level_read(8, &acpi_ec_status, &ec->common.status_addr);
+                        if (acpi_ec_status & ACPI_EC_FLAG_OBF)
+                                return 0;
+                        udelay(ACPI_EC_UDELAY);
+                } while (--i>0);
+                break;
+        case ACPI_EC_EVENT_IBE:
+                do {
+                        acpi_hw_low_level_read(8, &acpi_ec_status, &ec->common.status_addr);
+                        if (!(acpi_ec_status & ACPI_EC_FLAG_IBF))
+                                return 0;
+                        udelay(ACPI_EC_UDELAY);
+                } while (--i>0);
+                break;
+        default:
+                return -EINVAL;
+        }
+
+        return -ETIME;
+}
+static int acpi_ec_burst_wait(union acpi_ec *ec, unsigned int event)
 {
         int     result = 0;
 
         ACPI_FUNCTION_TRACE("acpi_ec_wait");
 
-        ec->expect_event = event;
+        ec->burst.expect_event = event;
         smp_mb();
 
-        result = wait_event_interruptible_timeout(ec->wait,
-                                        !ec->expect_event,
+        result = wait_event_interruptible_timeout(ec->burst.wait,
+                                        !ec->burst.expect_event,
                                         msecs_to_jiffies(ACPI_EC_DELAY));
         
-        ec->expect_event = 0;
+        ec->burst.expect_event = 0;
         smp_mb();
 
         if (result < 0){
@@ -160,7 +269,7 @@ static int acpi_ec_wait(struct acpi_ec *ec, unsigned int event)
 
 static int
 acpi_ec_enter_burst_mode (
-        struct acpi_ec          *ec)
+        union acpi_ec           *ec)
 {
         u32                     tmp = 0;
         int                     status = 0;
@@ -170,43 +279,43 @@ acpi_ec_enter_burst_mode (
         status = acpi_ec_read_status(ec);
         if (status != -EINVAL &&
                 !(status & ACPI_EC_FLAG_BURST)){
-                acpi_hw_low_level_write(8, ACPI_EC_BURST_ENABLE, &ec->command_addr);
+                acpi_hw_low_level_write(8, ACPI_EC_BURST_ENABLE, &ec->common.command_addr);
                 status = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
                 if (status){
-                        acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+                        acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
                         return_VALUE(-EINVAL);
                 }
-                acpi_hw_low_level_read(8, &tmp, &ec->data_addr);
-                acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+                acpi_hw_low_level_read(8, &tmp, &ec->common.data_addr);
+                acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
                 if(tmp != 0x90 ) {/* Burst ACK byte*/
                         return_VALUE(-EINVAL);
                 }
         }
 
-        atomic_set(&ec->leaving_burst , 0);
+        atomic_set(&ec->burst.leaving_burst , 0);
         return_VALUE(0);
 }
 
 static int
 acpi_ec_leave_burst_mode (
-        struct acpi_ec          *ec)
+        union acpi_ec           *ec)
 {
         int                     status =0;
 
         ACPI_FUNCTION_TRACE("acpi_ec_leave_burst_mode");
 
-        atomic_set(&ec->leaving_burst , 1);
+        atomic_set(&ec->burst.leaving_burst , 1);
         status = acpi_ec_read_status(ec);
         if (status != -EINVAL &&
                 (status & ACPI_EC_FLAG_BURST)){
-                acpi_hw_low_level_write(8, ACPI_EC_BURST_DISABLE, &ec->command_addr);
+                acpi_hw_low_level_write(8, ACPI_EC_BURST_DISABLE, &ec->common.command_addr);
                 status = acpi_ec_wait(ec, ACPI_EC_FLAG_IBF);
                 if (status){
-                        acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+                        acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
                         ACPI_DEBUG_PRINT((ACPI_DB_ERROR,"------->wait fail\n"));
                         return_VALUE(-EINVAL);
                 }
-                acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+                acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
                 status = acpi_ec_read_status(ec);
         }
 
@@ -215,7 +324,131 @@ acpi_ec_leave_burst_mode (
 
 static int
 acpi_ec_read (
-        struct acpi_ec          *ec,
+        union acpi_ec           *ec,
+        u8                      address,
+        u32                     *data)
+{
+        if (acpi_ec_polling_mode) 
+                return acpi_ec_polling_read(ec, address, data);
+        else
+                return acpi_ec_burst_read(ec, address, data);
+}
+static int
+acpi_ec_write (
+        union acpi_ec           *ec,
+        u8                      address,
+        u8                      data)
+{
+        if (acpi_ec_polling_mode) 
+                return acpi_ec_polling_write(ec, address, data);
+        else
+                return acpi_ec_burst_write(ec, address, data);
+}
+static int
+acpi_ec_polling_read (
+        union acpi_ec           *ec,
+        u8                      address,
+        u32                     *data)
+{
+        acpi_status             status = AE_OK;
+        int                     result = 0;
+        unsigned long           flags = 0;
+        u32                     glk = 0;
+
+        ACPI_FUNCTION_TRACE("acpi_ec_read");
+
+        if (!ec || !data)
+                return_VALUE(-EINVAL);
+
+        *data = 0;
+
+        if (ec->common.global_lock) {
+                status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
+                if (ACPI_FAILURE(status))
+                        return_VALUE(-ENODEV);
+        }
+
+        spin_lock_irqsave(&ec->polling.lock, flags);
+
+        acpi_hw_low_level_write(8, ACPI_EC_COMMAND_READ, &ec->common.command_addr);
+        result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
+        if (result)
+                goto end;
+
+        acpi_hw_low_level_write(8, address, &ec->common.data_addr);
+        result = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
+        if (result)
+                goto end;
+
+        acpi_hw_low_level_read(8, data, &ec->common.data_addr);
+
+        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Read [%02x] from address [%02x]\n",
+                *data, address));
+        
+end:
+        spin_unlock_irqrestore(&ec->polling.lock, flags);
+
+        if (ec->common.global_lock)
+                acpi_release_global_lock(glk);
+
+        return_VALUE(result);
+}
+
+
+static int
+acpi_ec_polling_write (
+        union acpi_ec           *ec,
+        u8                      address,
+        u8                      data)
+{
+        int                     result = 0;
+        acpi_status             status = AE_OK;
+        unsigned long           flags = 0;
+        u32                     glk = 0;
+
+        ACPI_FUNCTION_TRACE("acpi_ec_write");
+
+        if (!ec)
+                return_VALUE(-EINVAL);
+
+        if (ec->common.global_lock) {
+                status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
+                if (ACPI_FAILURE(status))
+                        return_VALUE(-ENODEV);
+        }
+
+        spin_lock_irqsave(&ec->polling.lock, flags);
+
+        acpi_hw_low_level_write(8, ACPI_EC_COMMAND_WRITE, &ec->common.command_addr);
+        result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
+        if (result)
+                goto end;
+
+        acpi_hw_low_level_write(8, address, &ec->common.data_addr);
+        result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
+        if (result)
+                goto end;
+
+        acpi_hw_low_level_write(8, data, &ec->common.data_addr);
+        result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
+        if (result)
+                goto end;
+
+        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Wrote [%02x] to address [%02x]\n",
+                data, address));
+
+end:
+        spin_unlock_irqrestore(&ec->polling.lock, flags);
+
+        if (ec->common.global_lock)
+                acpi_release_global_lock(glk);
+
+        return_VALUE(result);
+}
+
+static int
+acpi_ec_burst_read (
+        union acpi_ec           *ec,
         u8                      address,
         u32                     *data)
 {
@@ -230,51 +463,51 @@ acpi_ec_read (
 retry:
         *data = 0;
 
-        if (ec->global_lock) {
+        if (ec->common.global_lock) {
                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
                 if (ACPI_FAILURE(status))
                         return_VALUE(-ENODEV);
         }
 
         WARN_ON(in_interrupt());
-        down(&ec->sem);
+        down(&ec->burst.sem);
 
         if(acpi_ec_enter_burst_mode(ec))
                 goto end;
 
-        acpi_hw_low_level_write(8, ACPI_EC_COMMAND_READ, &ec->command_addr);
+        acpi_hw_low_level_write(8, ACPI_EC_COMMAND_READ, &ec->common.command_addr);
         status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
-        acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+        acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
         if (status) {
                 goto end;
         }
 
-        acpi_hw_low_level_write(8, address, &ec->data_addr);
+        acpi_hw_low_level_write(8, address, &ec->common.data_addr);
         status= acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
         if (status){
-                acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+                acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
                 goto end;
         }
 
-        acpi_hw_low_level_read(8, data, &ec->data_addr);
-        acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+        acpi_hw_low_level_read(8, data, &ec->common.data_addr);
+        acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
 
         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Read [%02x] from address [%02x]\n",
                 *data, address));
         
 end:
         acpi_ec_leave_burst_mode(ec);
-        up(&ec->sem);
+        up(&ec->burst.sem);
 
-        if (ec->global_lock)
+        if (ec->common.global_lock)
                 acpi_release_global_lock(glk);
 
-        if(atomic_read(&ec->leaving_burst) == 2){
+        if(atomic_read(&ec->burst.leaving_burst) == 2){
                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,"aborted, retry ...\n"));
-                while(atomic_read(&ec->pending_gpe)){
+                while(atomic_read(&ec->burst.pending_gpe)){
                         msleep(1);      
                 }
-                acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+                acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
                 goto retry;
         }
 
@@ -283,8 +516,8 @@ end:
 
 
 static int
-acpi_ec_write (
-        struct acpi_ec          *ec,
+acpi_ec_burst_write (
+        union acpi_ec           *ec,
         u8                      address,
         u8                      data)
 {
@@ -297,14 +530,14 @@ acpi_ec_write (
         if (!ec)
                 return_VALUE(-EINVAL);
 retry:
-        if (ec->global_lock) {
+        if (ec->common.global_lock) {
                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
                 if (ACPI_FAILURE(status))
                         return_VALUE(-ENODEV);
         }
 
         WARN_ON(in_interrupt());
-        down(&ec->sem);
+        down(&ec->burst.sem);
 
         if(acpi_ec_enter_burst_mode(ec))
                 goto end;
@@ -312,33 +545,33 @@ retry:
         status = acpi_ec_read_status(ec);
         if (status != -EINVAL &&
                 !(status & ACPI_EC_FLAG_BURST)){
-                acpi_hw_low_level_write(8, ACPI_EC_BURST_ENABLE, &ec->command_addr);
+                acpi_hw_low_level_write(8, ACPI_EC_BURST_ENABLE, &ec->common.command_addr);
                 status = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
                 if (status)
                         goto end;
-                acpi_hw_low_level_read(8, &tmp, &ec->data_addr);
+                acpi_hw_low_level_read(8, &tmp, &ec->common.data_addr);
                 if(tmp != 0x90 ) /* Burst ACK byte*/
                         goto end;
         }
         /*Now we are in burst mode*/
 
-        acpi_hw_low_level_write(8, ACPI_EC_COMMAND_WRITE, &ec->command_addr);
+        acpi_hw_low_level_write(8, ACPI_EC_COMMAND_WRITE, &ec->common.command_addr);
         status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
-        acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+        acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
         if (status){
                 goto end;
         }
 
-        acpi_hw_low_level_write(8, address, &ec->data_addr);
+        acpi_hw_low_level_write(8, address, &ec->common.data_addr);
         status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
         if (status){
-                acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+                acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
                 goto end;
         }
 
-        acpi_hw_low_level_write(8, data, &ec->data_addr);
+        acpi_hw_low_level_write(8, data, &ec->common.data_addr);
         status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
-        acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+        acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
         if (status)
                 goto end;
 
@@ -347,17 +580,17 @@ retry:
 
 end:
         acpi_ec_leave_burst_mode(ec);
-        up(&ec->sem);
+        up(&ec->burst.sem);
 
-        if (ec->global_lock)
+        if (ec->common.global_lock)
                 acpi_release_global_lock(glk);
 
-        if(atomic_read(&ec->leaving_burst) == 2){
+        if(atomic_read(&ec->burst.leaving_burst) == 2){
                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,"aborted, retry ...\n"));
-                while(atomic_read(&ec->pending_gpe)){
+                while(atomic_read(&ec->burst.pending_gpe)){
                         msleep(1);      
                 }
-                acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+                acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
                 goto retry;
         }
 
@@ -370,7 +603,7 @@ end:
 int
 ec_read(u8 addr, u8 *val)
 {
-        struct acpi_ec *ec;
+        union acpi_ec *ec;
         int err;
         u32 temp_data;
 
@@ -393,7 +626,7 @@ EXPORT_SYMBOL(ec_read);
 int
 ec_write(u8 addr, u8 val)
 {
-        struct acpi_ec *ec;
+        union acpi_ec *ec;
         int err;
 
         if (!first_ec)
@@ -407,10 +640,66 @@ ec_write(u8 addr, u8 val)
 }
 EXPORT_SYMBOL(ec_write);
 
-
 static int
 acpi_ec_query (
-        struct acpi_ec          *ec,
+        union acpi_ec           *ec,
+        u32                     *data)
+{
+        if (acpi_ec_polling_mode) 
+                return acpi_ec_polling_query(ec, data);
+        else
+                return acpi_ec_burst_query(ec, data);
+}
+static int
+acpi_ec_polling_query (
+        union acpi_ec           *ec,
+        u32                     *data)
+{
+        int                     result = 0;
+        acpi_status             status = AE_OK;
+        unsigned long           flags = 0;
+        u32                     glk = 0;
+
+        ACPI_FUNCTION_TRACE("acpi_ec_query");
+
+        if (!ec || !data)
+                return_VALUE(-EINVAL);
+
+        *data = 0;
+
+        if (ec->common.global_lock) {
+                status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
+                if (ACPI_FAILURE(status))
+                        return_VALUE(-ENODEV);
+        }
+
+        /*
+         * Query the EC to find out which _Qxx method we need to evaluate.
+         * Note that successful completion of the query causes the ACPI_EC_SCI
+         * bit to be cleared (and thus clearing the interrupt source).
+         */
+        spin_lock_irqsave(&ec->polling.lock, flags);
+
+        acpi_hw_low_level_write(8, ACPI_EC_COMMAND_QUERY, &ec->common.command_addr);
+        result = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
+        if (result)
+                goto end;
+
+        acpi_hw_low_level_read(8, data, &ec->common.data_addr);
+        if (!*data)
+                result = -ENODATA;
+
+end:
+        spin_unlock_irqrestore(&ec->polling.lock, flags);
+
+        if (ec->common.global_lock)
+                acpi_release_global_lock(glk);
+
+        return_VALUE(result);
+}
+static int
+acpi_ec_burst_query (
+        union acpi_ec           *ec,
         u32                     *data)
 {
         int                     status = 0;
@@ -422,13 +711,13 @@ acpi_ec_query (
                 return_VALUE(-EINVAL);
         *data = 0;
 
-        if (ec->global_lock) {
+        if (ec->common.global_lock) {
                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
                 if (ACPI_FAILURE(status))
                         return_VALUE(-ENODEV);
         }
 
-        down(&ec->sem);
+        down(&ec->burst.sem);
         if(acpi_ec_enter_burst_mode(ec))
                 goto end;
         /*
@@ -436,28 +725,28 @@ acpi_ec_query (
          * Note that successful completion of the query causes the ACPI_EC_SCI
          * bit to be cleared (and thus clearing the interrupt source).
          */
-        acpi_hw_low_level_write(8, ACPI_EC_COMMAND_QUERY, &ec->command_addr);
+        acpi_hw_low_level_write(8, ACPI_EC_COMMAND_QUERY, &ec->common.command_addr);
         status = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
         if (status){
-                acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+                acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
                 goto end;
         }
 
-        acpi_hw_low_level_read(8, data, &ec->data_addr);
-        acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+        acpi_hw_low_level_read(8, data, &ec->common.data_addr);
+        acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
         if (!*data)
                 status = -ENODATA;
 
 end:
         acpi_ec_leave_burst_mode(ec);
-        up(&ec->sem);
+        up(&ec->burst.sem);
 
-        if (ec->global_lock)
+        if (ec->common.global_lock)
                 acpi_release_global_lock(glk);
 
-        if(atomic_read(&ec->leaving_burst) == 2){
+        if(atomic_read(&ec->burst.leaving_burst) == 2){
                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,"aborted, retry ...\n"));
-                acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+                acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
                 status = -ENODATA;
         }
         return_VALUE(status);
@@ -468,7 +757,7 @@ end:
                                 Event Management
    -------------------------------------------------------------------------- */
 
-struct acpi_ec_query_data {
+union acpi_ec_query_data {
         acpi_handle             handle;
         u8                      data;
 };
@@ -477,7 +766,59 @@ static void
 acpi_ec_gpe_query (
         void                    *ec_cxt)
 {
-        struct acpi_ec          *ec = (struct acpi_ec *) ec_cxt;
+        if (acpi_ec_polling_mode) 
+                acpi_ec_gpe_polling_query(ec_cxt);
+        else
+                acpi_ec_gpe_burst_query(ec_cxt);
+}
+
+static void
+acpi_ec_gpe_polling_query (
+        void                    *ec_cxt)
+{
+        union acpi_ec           *ec = (union acpi_ec *) ec_cxt;
+        u32                     value = 0;
+        unsigned long           flags = 0;
+        static char             object_name[5] = {'_','Q','0','0','\0'};
+        const char              hex[] = {'0','1','2','3','4','5','6','7',
+                                         '8','9','A','B','C','D','E','F'};
+
+        ACPI_FUNCTION_TRACE("acpi_ec_gpe_query");
+
+        if (!ec_cxt)
+                goto end;
+
+        spin_lock_irqsave(&ec->polling.lock, flags);
+        acpi_hw_low_level_read(8, &value, &ec->common.command_addr);
+        spin_unlock_irqrestore(&ec->polling.lock, flags);
+
+        /* TBD: Implement asynch events!
+         * NOTE: All we care about are EC-SCI's.  Other EC events are
+         * handled via polling (yuck!).  This is because some systems
+         * treat EC-SCIs as level (versus EDGE!) triggered, preventing
+         *  a purely interrupt-driven approach (grumble, grumble).
+         */
+        if (!(value & ACPI_EC_FLAG_SCI))
+                goto end;
+
+        if (acpi_ec_query(ec, &value))
+                goto end;
+
+        object_name[2] = hex[((value >> 4) & 0x0F)];
+        object_name[3] = hex[(value & 0x0F)];
+
+        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Evaluating %s\n", object_name));
+
+        acpi_evaluate_object(ec->common.handle, object_name, NULL, NULL);
+
+end:    
+        acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
+}
+static void
+acpi_ec_gpe_burst_query (
+        void                    *ec_cxt)
+{
+        union acpi_ec           *ec = (union acpi_ec *) ec_cxt;
         u32                     value;
         int                     result = -ENODATA;
         static char             object_name[5] = {'_','Q','0','0','\0'};
@@ -497,9 +838,9 @@ acpi_ec_gpe_query (
 
         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Evaluating %s\n", object_name));
 
-        acpi_evaluate_object(ec->handle, object_name, NULL, NULL);
+        acpi_evaluate_object(ec->common.handle, object_name, NULL, NULL);
 end:    
-        atomic_dec(&ec->pending_gpe);
+        atomic_dec(&ec->burst.pending_gpe);
         return;
 }
 
@@ -507,48 +848,77 @@ static u32
 acpi_ec_gpe_handler (
         void                    *data)
 {
+        if (acpi_ec_polling_mode) 
+                return acpi_ec_gpe_polling_handler(data);
+        else
+                return acpi_ec_gpe_burst_handler(data); 
+}
+static u32
+acpi_ec_gpe_polling_handler (
+        void                    *data)
+{
+        acpi_status             status = AE_OK;
+        union acpi_ec           *ec = (union acpi_ec *) data;
+
+        if (!ec)
+                return ACPI_INTERRUPT_NOT_HANDLED;
+
+        acpi_disable_gpe(NULL, ec->common.gpe_bit, ACPI_ISR);
+
+        status = acpi_os_queue_for_execution(OSD_PRIORITY_GPE,
+                acpi_ec_gpe_query, ec);
+
+        if (status == AE_OK)
+                return ACPI_INTERRUPT_HANDLED;
+        else
+                return ACPI_INTERRUPT_NOT_HANDLED;
+}
+static u32
+acpi_ec_gpe_burst_handler (
+        void                    *data)
+{
         acpi_status             status = AE_OK;
         u32                     value;
-        struct acpi_ec          *ec = (struct acpi_ec *) data;
+        union acpi_ec           *ec = (union acpi_ec *) data;
 
         if (!ec)
                 return ACPI_INTERRUPT_NOT_HANDLED;
 
-        acpi_disable_gpe(NULL, ec->gpe_bit, ACPI_ISR);
+        acpi_disable_gpe(NULL, ec->common.gpe_bit, ACPI_ISR);
 
         value = acpi_ec_read_status(ec);
 
         if((value & ACPI_EC_FLAG_IBF) &&
                 !(value & ACPI_EC_FLAG_BURST) &&
-                        (atomic_read(&ec->leaving_burst) == 0)) { 
+                        (atomic_read(&ec->burst.leaving_burst) == 0)) { 
         /*
          * the embedded controller disables 
          * burst mode for any reason other 
          * than the burst disable command
          * to process critical event.
          */
-                atomic_set(&ec->leaving_burst , 2); /* block current pending transaction
+                atomic_set(&ec->burst.leaving_burst , 2); /* block current pending transaction
                                         and retry */
-                wake_up(&ec->wait);
+                wake_up(&ec->burst.wait);
         }else {
-                if ((ec->expect_event == ACPI_EC_EVENT_OBF &&
+                if ((ec->burst.expect_event == ACPI_EC_EVENT_OBF &&
                                 (value & ACPI_EC_FLAG_OBF)) ||
-                                (ec->expect_event == ACPI_EC_EVENT_IBE &&
+                                (ec->burst.expect_event == ACPI_EC_EVENT_IBE &&
                                 !(value & ACPI_EC_FLAG_IBF))) {
-                        ec->expect_event = 0;
-                        wake_up(&ec->wait);
+                        ec->burst.expect_event = 0;
+                        wake_up(&ec->burst.wait);
                         return ACPI_INTERRUPT_HANDLED;
                 }
         }
 
         if (value & ACPI_EC_FLAG_SCI){
-                atomic_add(1, &ec->pending_gpe) ;
+                atomic_add(1, &ec->burst.pending_gpe) ;
                 status = acpi_os_queue_for_execution(OSD_PRIORITY_GPE,
                                                 acpi_ec_gpe_query, ec);
                 return status == AE_OK ?
                 ACPI_INTERRUPT_HANDLED : ACPI_INTERRUPT_NOT_HANDLED;
         } 
-        acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_ISR);
+        acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_ISR);
         return status == AE_OK ?
                 ACPI_INTERRUPT_HANDLED : ACPI_INTERRUPT_NOT_HANDLED;
 }
@@ -585,7 +955,7 @@ acpi_ec_space_handler (
         void                    *region_context)
 {
         int                     result = 0;
-        struct acpi_ec          *ec = NULL;
+        union acpi_ec           *ec = NULL;
         u64                     temp = *value;
         acpi_integer            f_v = 0;
         int                     i = 0;
@@ -600,7 +970,7 @@ acpi_ec_space_handler (
                 return_VALUE(AE_BAD_PARAMETER);
         }
 
-        ec = (struct acpi_ec *) handler_context;
+        ec = (union acpi_ec *) handler_context;
 
 next_byte:
         switch (function) {
@@ -661,7 +1031,7 @@ static struct proc_dir_entry	*acpi_ec_dir;
 static int
 acpi_ec_read_info (struct seq_file *seq, void *offset)
 {
-        struct acpi_ec          *ec = (struct acpi_ec *) seq->private;
+        union acpi_ec           *ec = (union acpi_ec *) seq->private;
 
         ACPI_FUNCTION_TRACE("acpi_ec_read_info");
 
@@ -669,12 +1039,12 @@ acpi_ec_read_info (struct seq_file *seq, void *offset)
                 goto end;
 
         seq_printf(seq, "gpe bit:                 0x%02x\n",
-                (u32) ec->gpe_bit);
+                (u32) ec->common.gpe_bit);
         seq_printf(seq, "ports:                   0x%02x, 0x%02x\n",
-                (u32) ec->status_addr.address, (u32) ec->data_addr.address);
+                (u32) ec->common.status_addr.address, (u32) ec->common.data_addr.address);
         seq_printf(seq, "use global lock:         %s\n",
-                ec->global_lock?"yes":"no");
-        acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+                ec->common.global_lock?"yes":"no");
+        acpi_enable_gpe(NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
 
 end:
         return_VALUE(0);
@@ -697,7 +1067,7 @@ static int
 acpi_ec_add_fs (
         struct acpi_device      *device)
 {
-        struct proc_dir_entry   *entry;
+        struct proc_dir_entry   *entry = NULL;
 
         ACPI_FUNCTION_TRACE("acpi_ec_add_fs");
 
@@ -744,13 +1114,82 @@ acpi_ec_remove_fs (
                                Driver Interface
    -------------------------------------------------------------------------- */
 
+
 static int
-acpi_ec_add (
+acpi_ec_polling_add (
         struct acpi_device      *device)
 {
-        int                     result;
-        acpi_status             status;
-        struct acpi_ec          *ec;
+        int                     result = 0;
+        acpi_status             status = AE_OK;
+        union acpi_ec           *ec = NULL;
+        unsigned long           uid;
+
+        ACPI_FUNCTION_TRACE("acpi_ec_add");
+
+        if (!device)
+                return_VALUE(-EINVAL);
+
+        ec = kmalloc(sizeof(union acpi_ec), GFP_KERNEL);
+        if (!ec)
+                return_VALUE(-ENOMEM);
+        memset(ec, 0, sizeof(union acpi_ec));
+
+        ec->common.handle = device->handle;
+        ec->common.uid = -1;
+        spin_lock_init(&ec->polling.lock);
+        strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
+        strcpy(acpi_device_class(device), ACPI_EC_CLASS);
+        acpi_driver_data(device) = ec;
+
+        /* Use the global lock for all EC transactions? */
+        acpi_evaluate_integer(ec->common.handle, "_GLK", NULL, &ec->common.global_lock);
+
+        /* If our UID matches the UID for the ECDT-enumerated EC,
+           we now have the *real* EC info, so kill the makeshift one.*/
+        acpi_evaluate_integer(ec->common.handle, "_UID", NULL, &uid);
+        if (ec_ecdt && ec_ecdt->common.uid == uid) {
+                acpi_remove_address_space_handler(ACPI_ROOT_OBJECT,
+                        ACPI_ADR_SPACE_EC, &acpi_ec_space_handler);
+        
+                acpi_remove_gpe_handler(NULL, ec_ecdt->common.gpe_bit, &acpi_ec_gpe_handler);
+
+                kfree(ec_ecdt);
+        }
+
+        /* Get GPE bit assignment (EC events). */
+        /* TODO: Add support for _GPE returning a package */
+        status = acpi_evaluate_integer(ec->common.handle, "_GPE", NULL, &ec->common.gpe_bit);
+        if (ACPI_FAILURE(status)) {
+                ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
+                        "Error obtaining GPE bit assignment\n"));
+                result = -ENODEV;
+                goto end;
+        }
+
+        result = acpi_ec_add_fs(device);
+        if (result)
+                goto end;
+
+        printk(KERN_INFO PREFIX "%s [%s] (gpe %d)\n",
+                acpi_device_name(device), acpi_device_bid(device),
+                (u32) ec->common.gpe_bit);
+
+        if (!first_ec)
+                first_ec = device;
+
+end:
+        if (result)
+                kfree(ec);
+
+        return_VALUE(result);
+}
+static int
+acpi_ec_burst_add (
+        struct acpi_device      *device)
+{
+        int                     result = 0;
+        acpi_status             status = AE_OK;
+        union acpi_ec           *ec = NULL;
         unsigned long           uid;
 
         ACPI_FUNCTION_TRACE("acpi_ec_add");
@@ -758,39 +1197,39 @@ acpi_ec_add (
         if (!device)
                 return_VALUE(-EINVAL);
 
-        ec = kmalloc(sizeof(struct acpi_ec), GFP_KERNEL);
+        ec = kmalloc(sizeof(union acpi_ec), GFP_KERNEL);
         if (!ec)
                 return_VALUE(-ENOMEM);
-        memset(ec, 0, sizeof(struct acpi_ec));
-
-        ec->handle = device->handle;
-        ec->uid = -1;
-        atomic_set(&ec->pending_gpe, 0);
-        atomic_set(&ec->leaving_burst , 1);
-        init_MUTEX(&ec->sem);
-        init_waitqueue_head(&ec->wait);
+        memset(ec, 0, sizeof(union acpi_ec));
+
+        ec->common.handle = device->handle;
+        ec->common.uid = -1;
+        atomic_set(&ec->burst.pending_gpe, 0);
+        atomic_set(&ec->burst.leaving_burst , 1);
+        init_MUTEX(&ec->burst.sem);
+        init_waitqueue_head(&ec->burst.wait);
         strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
         strcpy(acpi_device_class(device), ACPI_EC_CLASS);
         acpi_driver_data(device) = ec;
 
         /* Use the global lock for all EC transactions? */
-        acpi_evaluate_integer(ec->handle, "_GLK", NULL, &ec->global_lock);
+        acpi_evaluate_integer(ec->common.handle, "_GLK", NULL, &ec->common.global_lock);
 
         /* If our UID matches the UID for the ECDT-enumerated EC,
            we now have the *real* EC info, so kill the makeshift one.*/
-        acpi_evaluate_integer(ec->handle, "_UID", NULL, &uid);
-        if (ec_ecdt && ec_ecdt->uid == uid) {
+        acpi_evaluate_integer(ec->common.handle, "_UID", NULL, &uid);
+        if (ec_ecdt && ec_ecdt->common.uid == uid) {
                 acpi_remove_address_space_handler(ACPI_ROOT_OBJECT,
                         ACPI_ADR_SPACE_EC, &acpi_ec_space_handler);
 
-                acpi_remove_gpe_handler(NULL, ec_ecdt->gpe_bit, &acpi_ec_gpe_handler);
+                acpi_remove_gpe_handler(NULL, ec_ecdt->common.gpe_bit, &acpi_ec_gpe_handler);
 
                 kfree(ec_ecdt);
         }
 
         /* Get GPE bit assignment (EC events). */
         /* TODO: Add support for _GPE returning a package */
-        status = acpi_evaluate_integer(ec->handle, "_GPE", NULL, &ec->gpe_bit);
+        status = acpi_evaluate_integer(ec->common.handle, "_GPE", NULL, &ec->common.gpe_bit);
         if (ACPI_FAILURE(status)) {
                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
                         "Error obtaining GPE bit assignment\n"));
@@ -804,7 +1243,7 @@ acpi_ec_add (
 
         printk(KERN_INFO PREFIX "%s [%s] (gpe %d)\n",
                 acpi_device_name(device), acpi_device_bid(device),
-                (u32) ec->gpe_bit);
+                (u32) ec->common.gpe_bit);
 
         if (!first_ec)
                 first_ec = device;
@@ -822,7 +1261,7 @@ acpi_ec_remove (
         struct acpi_device      *device,
         int                     type)
 {
-        struct acpi_ec          *ec;
+        union acpi_ec           *ec = NULL;
 
         ACPI_FUNCTION_TRACE("acpi_ec_remove");
 
@@ -844,7 +1283,7 @@ acpi_ec_io_ports (
         struct acpi_resource    *resource,
         void                    *context)
 {
-        struct acpi_ec          *ec = (struct acpi_ec *) context;
+        union acpi_ec           *ec = (union acpi_ec *) context;
         struct acpi_generic_address *addr;
 
         if (resource->id != ACPI_RSTYPE_IO) {
@@ -856,10 +1295,10 @@ acpi_ec_io_ports (
          * the second address region returned is the status/command
          * port.
          */
-        if (ec->data_addr.register_bit_width == 0) {
-                addr = &ec->data_addr;
-        } else if (ec->command_addr.register_bit_width == 0) {
-                addr = &ec->command_addr;
+        if (ec->common.data_addr.register_bit_width == 0) {
+                addr = &ec->common.data_addr;
+        } else if (ec->common.command_addr.register_bit_width == 0) {
+                addr = &ec->common.command_addr;
         } else {
                 return AE_CTRL_TERMINATE;
         }
@@ -877,8 +1316,8 @@ static int
 acpi_ec_start (
         struct acpi_device      *device)
 {
-        acpi_status             status;
-        struct acpi_ec          *ec;
+        acpi_status             status = AE_OK;
+        union acpi_ec           *ec = NULL;
 
         ACPI_FUNCTION_TRACE("acpi_ec_start");
 
@@ -893,35 +1332,36 @@ acpi_ec_start (
         /*
          * Get I/O port addresses. Convert to GAS format.
          */
-        status = acpi_walk_resources(ec->handle, METHOD_NAME__CRS,
+        status = acpi_walk_resources(ec->common.handle, METHOD_NAME__CRS,
                 acpi_ec_io_ports, ec);
-        if (ACPI_FAILURE(status) || ec->command_addr.register_bit_width == 0) {
+        if (ACPI_FAILURE(status) || ec->common.command_addr.register_bit_width == 0) {
                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error getting I/O port addresses"));
                 return_VALUE(-ENODEV);
         }
 
-        ec->status_addr = ec->command_addr;
+        ec->common.status_addr = ec->common.command_addr;
 
         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "gpe=0x%02x, ports=0x%2x,0x%2x\n",
-                (u32) ec->gpe_bit, (u32) ec->command_addr.address,
-                (u32) ec->data_addr.address));
+                (u32) ec->common.gpe_bit, (u32) ec->common.command_addr.address,
+                (u32) ec->common.data_addr.address));
+
 
         /*
          * Install GPE handler
          */
-        status = acpi_install_gpe_handler(NULL, ec->gpe_bit,
+        status = acpi_install_gpe_handler(NULL, ec->common.gpe_bit,
                 ACPI_GPE_EDGE_TRIGGERED, &acpi_ec_gpe_handler, ec);
         if (ACPI_FAILURE(status)) {
                 return_VALUE(-ENODEV);
         }
-        acpi_set_gpe_type (NULL, ec->gpe_bit, ACPI_GPE_TYPE_RUNTIME);
-        acpi_enable_gpe (NULL, ec->gpe_bit, ACPI_NOT_ISR);
+        acpi_set_gpe_type (NULL, ec->common.gpe_bit, ACPI_GPE_TYPE_RUNTIME);
+        acpi_enable_gpe (NULL, ec->common.gpe_bit, ACPI_NOT_ISR);
 
-        status = acpi_install_address_space_handler (ec->handle,
+        status = acpi_install_address_space_handler (ec->common.handle,
                         ACPI_ADR_SPACE_EC, &acpi_ec_space_handler,
                         &acpi_ec_space_setup, ec);
         if (ACPI_FAILURE(status)) {
-                acpi_remove_gpe_handler(NULL, ec->gpe_bit, &acpi_ec_gpe_handler);
+                acpi_remove_gpe_handler(NULL, ec->common.gpe_bit, &acpi_ec_gpe_handler);
                 return_VALUE(-ENODEV);
         }
 
@@ -934,8 +1374,8 @@ acpi_ec_stop (
         struct acpi_device      *device,
         int                     type)
 {
-        acpi_status             status;
-        struct acpi_ec          *ec;
+        acpi_status             status = AE_OK;
+        union acpi_ec           *ec = NULL;
 
         ACPI_FUNCTION_TRACE("acpi_ec_stop");
 
@@ -944,12 +1384,12 @@ acpi_ec_stop (
 
         ec = acpi_driver_data(device);
 
-        status = acpi_remove_address_space_handler(ec->handle,
+        status = acpi_remove_address_space_handler(ec->common.handle,
                 ACPI_ADR_SPACE_EC, &acpi_ec_space_handler);
         if (ACPI_FAILURE(status))
                 return_VALUE(-ENODEV);
 
-        status = acpi_remove_gpe_handler(NULL, ec->gpe_bit, &acpi_ec_gpe_handler);
+        status = acpi_remove_gpe_handler(NULL, ec->common.gpe_bit, &acpi_ec_gpe_handler);
         if (ACPI_FAILURE(status))
                 return_VALUE(-ENODEV);
 
@@ -963,26 +1403,76 @@ acpi_fake_ecdt_callback (
         void            *context,
         void            **retval)
 {
+
+        if (acpi_ec_polling_mode)
+                return acpi_fake_ecdt_polling_callback(handle,
+                        Level, context, retval);
+        else
+                return acpi_fake_ecdt_burst_callback(handle,
+                        Level, context, retval);
+}
+
+static acpi_status __init
+acpi_fake_ecdt_polling_callback (
+        acpi_handle     handle,
+        u32             Level,
+        void            *context,
+        void            **retval)
+{
+        acpi_status     status;
+
+        status = acpi_walk_resources(handle, METHOD_NAME__CRS,
+                acpi_ec_io_ports, ec_ecdt);
+        if (ACPI_FAILURE(status))
+                return status;
+        ec_ecdt->common.status_addr = ec_ecdt->common.command_addr;
+
+        ec_ecdt->common.uid = -1;
+        acpi_evaluate_integer(handle, "_UID", NULL, &ec_ecdt->common.uid);
+
+        status = acpi_evaluate_integer(handle, "_GPE", NULL, &ec_ecdt->common.gpe_bit);
+        if (ACPI_FAILURE(status))
+                return status;
+        spin_lock_init(&ec_ecdt->polling.lock);
+        ec_ecdt->common.global_lock = TRUE;
+        ec_ecdt->common.handle = handle;
+
+        printk(KERN_INFO PREFIX  "GPE=0x%02x, ports=0x%2x, 0x%2x\n",
+                (u32) ec_ecdt->common.gpe_bit, (u32) ec_ecdt->common.command_addr.address,
+                (u32) ec_ecdt->common.data_addr.address);
+
+        return AE_CTRL_TERMINATE;
+}
+
+static acpi_status __init
+acpi_fake_ecdt_burst_callback (
+        acpi_handle     handle,
+        u32             Level,
+        void            *context,
+        void            **retval)
+{
         acpi_status     status;
 
+        init_MUTEX(&ec_ecdt->burst.sem);
+        init_waitqueue_head(&ec_ecdt->burst.wait);
         status = acpi_walk_resources(handle, METHOD_NAME__CRS,
                 acpi_ec_io_ports, ec_ecdt);
         if (ACPI_FAILURE(status))
                 return status;
-        ec_ecdt->status_addr = ec_ecdt->command_addr;
+        ec_ecdt->common.status_addr = ec_ecdt->common.command_addr;
 
-        ec_ecdt->uid = -1;
-        acpi_evaluate_integer(handle, "_UID", NULL, &ec_ecdt->uid);
+        ec_ecdt->common.uid = -1;
+        acpi_evaluate_integer(handle, "_UID", NULL, &ec_ecdt->common.uid);
 
-        status = acpi_evaluate_integer(handle, "_GPE", NULL, &ec_ecdt->gpe_bit);
+        status = acpi_evaluate_integer(handle, "_GPE", NULL, &ec_ecdt->common.gpe_bit);
         if (ACPI_FAILURE(status))
                 return status;
-        ec_ecdt->global_lock = TRUE;
-        ec_ecdt->handle = handle;
+        ec_ecdt->common.global_lock = TRUE;
+        ec_ecdt->common.handle = handle;
 
         printk(KERN_INFO PREFIX  "GPE=0x%02x, ports=0x%2x, 0x%2x\n",
-                (u32) ec_ecdt->gpe_bit, (u32) ec_ecdt->command_addr.address,
-                (u32) ec_ecdt->data_addr.address);
+                (u32) ec_ecdt->common.gpe_bit, (u32) ec_ecdt->common.command_addr.address,
+                (u32) ec_ecdt->common.data_addr.address);
 
         return AE_CTRL_TERMINATE;
 }
@@ -1005,12 +1495,12 @@ acpi_ec_fake_ecdt(void)
 
         printk(KERN_INFO PREFIX "Try to make an fake ECDT\n");
 
-        ec_ecdt = kmalloc(sizeof(struct acpi_ec), GFP_KERNEL);
+        ec_ecdt = kmalloc(sizeof(union acpi_ec), GFP_KERNEL);
         if (!ec_ecdt) {
                 ret = -ENOMEM;
                 goto error;
         }
-        memset(ec_ecdt, 0, sizeof(struct acpi_ec));
+        memset(ec_ecdt, 0, sizeof(union acpi_ec));
 
         status = acpi_get_devices (ACPI_EC_HID,
                                 acpi_fake_ecdt_callback,
@@ -1031,6 +1521,60 @@ error:
 static int __init
 acpi_ec_get_real_ecdt(void)
 {
+        if (acpi_ec_polling_mode)
+                return acpi_ec_polling_get_real_ecdt();
+        else
+                return acpi_ec_burst_get_real_ecdt();
+}
+
+static int __init
+acpi_ec_polling_get_real_ecdt(void)
+{
+        acpi_status             status;
+        struct acpi_table_ecdt  *ecdt_ptr;
+
+        status = acpi_get_firmware_table("ECDT", 1, ACPI_LOGICAL_ADDRESSING, 
+                (struct acpi_table_header **) &ecdt_ptr);
+        if (ACPI_FAILURE(status))
+                return -ENODEV;
+
+        printk(KERN_INFO PREFIX "Found ECDT\n");
+
+        /*
+         * Generate a temporary ec context to use until the namespace is scanned
+         */
+        ec_ecdt = kmalloc(sizeof(union acpi_ec), GFP_KERNEL);
+        if (!ec_ecdt)
+                return -ENOMEM;
+        memset(ec_ecdt, 0, sizeof(union acpi_ec));
+
+        ec_ecdt->common.command_addr = ecdt_ptr->ec_control;
+        ec_ecdt->common.status_addr = ecdt_ptr->ec_control;
+        ec_ecdt->common.data_addr = ecdt_ptr->ec_data;
+        ec_ecdt->common.gpe_bit = ecdt_ptr->gpe_bit;
+        spin_lock_init(&ec_ecdt->polling.lock);
+        /* use the GL just to be safe */
+        ec_ecdt->common.global_lock = TRUE;
+        ec_ecdt->common.uid = ecdt_ptr->uid;
+
+        status = acpi_get_handle(NULL, ecdt_ptr->ec_id, &ec_ecdt->common.handle);
+        if (ACPI_FAILURE(status)) {
+                goto error;
+        }
+
+        return 0;
+error:
+        printk(KERN_ERR PREFIX "Could not use ECDT\n");
+        kfree(ec_ecdt);
+        ec_ecdt = NULL;
+
+        return -ENODEV;
+}
+
+
+static int __init
+acpi_ec_burst_get_real_ecdt(void)
+{
         acpi_status             status;
         struct acpi_table_ecdt  *ecdt_ptr;
 
@@ -1044,22 +1588,22 @@ acpi_ec_get_real_ecdt(void)
         /*
          * Generate a temporary ec context to use until the namespace is scanned
          */
-        ec_ecdt = kmalloc(sizeof(struct acpi_ec), GFP_KERNEL);
+        ec_ecdt = kmalloc(sizeof(union acpi_ec), GFP_KERNEL);
         if (!ec_ecdt)
                 return -ENOMEM;
-        memset(ec_ecdt, 0, sizeof(struct acpi_ec));
-
-        init_MUTEX(&ec_ecdt->sem);
-        init_waitqueue_head(&ec_ecdt->wait);
-        ec_ecdt->command_addr = ecdt_ptr->ec_control;
-        ec_ecdt->status_addr = ecdt_ptr->ec_control;
-        ec_ecdt->data_addr = ecdt_ptr->ec_data;
-        ec_ecdt->gpe_bit = ecdt_ptr->gpe_bit;
+        memset(ec_ecdt, 0, sizeof(union acpi_ec));
+
+        init_MUTEX(&ec_ecdt->burst.sem);
+        init_waitqueue_head(&ec_ecdt->burst.wait);
+        ec_ecdt->common.command_addr = ecdt_ptr->ec_control;
+        ec_ecdt->common.status_addr = ecdt_ptr->ec_control;
+        ec_ecdt->common.data_addr = ecdt_ptr->ec_data;
+        ec_ecdt->common.gpe_bit = ecdt_ptr->gpe_bit;
         /* use the GL just to be safe */
-        ec_ecdt->global_lock = TRUE;
-        ec_ecdt->uid = ecdt_ptr->uid;
+        ec_ecdt->common.global_lock = TRUE;
+        ec_ecdt->common.uid = ecdt_ptr->uid;
 
-        status = acpi_get_handle(NULL, ecdt_ptr->ec_id, &ec_ecdt->handle);
+        status = acpi_get_handle(NULL, ecdt_ptr->ec_id, &ec_ecdt->common.handle);
         if (ACPI_FAILURE(status)) {
                 goto error;
         }
@@ -1092,20 +1636,20 @@ acpi_ec_ecdt_probe (void)
         /*
          * Install GPE handler
          */
-        status = acpi_install_gpe_handler(NULL, ec_ecdt->gpe_bit,
+        status = acpi_install_gpe_handler(NULL, ec_ecdt->common.gpe_bit,
                 ACPI_GPE_EDGE_TRIGGERED, &acpi_ec_gpe_handler,
                 ec_ecdt);
         if (ACPI_FAILURE(status)) {
                 goto error;
         }
-        acpi_set_gpe_type (NULL, ec_ecdt->gpe_bit, ACPI_GPE_TYPE_RUNTIME);
-        acpi_enable_gpe (NULL, ec_ecdt->gpe_bit, ACPI_NOT_ISR);
+        acpi_set_gpe_type (NULL, ec_ecdt->common.gpe_bit, ACPI_GPE_TYPE_RUNTIME);
+        acpi_enable_gpe (NULL, ec_ecdt->common.gpe_bit, ACPI_NOT_ISR);
 
         status = acpi_install_address_space_handler (ACPI_ROOT_OBJECT,
                         ACPI_ADR_SPACE_EC, &acpi_ec_space_handler,
                         &acpi_ec_space_setup, ec_ecdt);
         if (ACPI_FAILURE(status)) {
-                acpi_remove_gpe_handler(NULL, ec_ecdt->gpe_bit,
+                acpi_remove_gpe_handler(NULL, ec_ecdt->common.gpe_bit,
                         &acpi_ec_gpe_handler);
                 goto error;
         }
@@ -1123,7 +1667,7 @@ error:
 
 static int __init acpi_ec_init (void)
 {
-        int                     result;
+        int                     result = 0;
 
         ACPI_FUNCTION_TRACE("acpi_ec_init");
 
@@ -1167,3 +1711,10 @@ static int __init acpi_fake_ecdt_setup(char *str)
         return 0;
 }
 __setup("acpi_fake_ecdt", acpi_fake_ecdt_setup);
+static int __init acpi_ec_set_polling_mode(char *str)
+{
+        acpi_ec_polling_mode = EC_POLLING;
+        acpi_ec_driver.ops.add = acpi_ec_polling_add;
+        return 0;
+}
+__setup("ec_polling", acpi_ec_set_polling_mode);