[ACPI] Enable EC Burst Mode

Fixes several Embedded Controller issues, including
button failure and battery status AE_TIME failure.

http://bugzilla.kernel.org/show_bug.cgi?id=3851

Based on patch by: Andi Kleen <ak@suse.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Luming Yu <luming.yu@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 276 insertions, 114 deletions

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index fdf143b405be..69b04d430f00 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -31,6 +31,7 @@
 #include <linux/delay.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
+#include <linux/interrupt.h>
 #include <asm/io.h>
 #include <acpi/acpi_bus.h>
 #include <acpi/acpi_drivers.h>
@@ -49,17 +50,19 @@ ACPI_MODULE_NAME		("acpi_ec")
 
 #define ACPI_EC_FLAG_OBF        0x01    /* Output buffer full */
 #define ACPI_EC_FLAG_IBF        0x02    /* Input buffer full */
+#define ACPI_EC_FLAG_BURST      0x10    /* burst mode */
 #define ACPI_EC_FLAG_SCI        0x20    /* EC-SCI occurred */
 
 #define ACPI_EC_EVENT_OBF       0x01    /* Output buffer full */
 #define ACPI_EC_EVENT_IBE       0x02    /* Input buffer empty */
 
-#define ACPI_EC_UDELAY          100     /* Poll @ 100us increments */
-#define ACPI_EC_UDELAY_COUNT    1000    /* Wait 10ms max. during EC ops */
+#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_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);
@@ -87,7 +90,11 @@ struct acpi_ec {
         struct acpi_generic_address     command_addr;
         struct acpi_generic_address     data_addr;
         unsigned long                   global_lock;
-        spinlock_t                      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;
 };
 
 /* If we find an EC via the ECDT, we need to keep a ptr to its context */
@@ -100,59 +107,138 @@ static struct acpi_device *first_ec;
                              Transaction Management
    -------------------------------------------------------------------------- */
 
-static int
-acpi_ec_wait (
-        struct acpi_ec          *ec,
-        u8                      event)
+static inline u32 acpi_ec_read_status(struct acpi_ec *ec)
 {
-        u32                     acpi_ec_status = 0;
-        u32                     i = ACPI_EC_UDELAY_COUNT;
+        u32     status = 0;
 
-        if (!ec)
-                return -EINVAL;
+        acpi_hw_low_level_read(8, &status, &ec->status_addr);
+        return status;
+}
+
+static int acpi_ec_wait(struct acpi_ec *ec, unsigned int event)
+{
+        int     result = 0;
+
+        ACPI_FUNCTION_TRACE("acpi_ec_wait");
 
-        /* Poll the EC status register waiting for the event to occur. */
+        ec->expect_event = event;
+        smp_mb();
+
+        result = wait_event_interruptible_timeout(ec->wait,
+                                        !ec->expect_event,
+                                        msecs_to_jiffies(ACPI_EC_DELAY));
+        
+        ec->expect_event = 0;
+        smp_mb();
+
+        if (result < 0){
+                ACPI_DEBUG_PRINT((ACPI_DB_ERROR," result  = %d ", result));
+                return_VALUE(result);
+        }
+
+        /*
+         * Verify that the event in question has actually happened by
+         * querying EC status. Do the check even if operation timed-out
+         * to make sure that we did not miss interrupt.
+         */
         switch (event) {
         case ACPI_EC_EVENT_OBF:
-                do {
-                        acpi_hw_low_level_read(8, &acpi_ec_status, &ec->status_addr);
-                        if (acpi_ec_status & ACPI_EC_FLAG_OBF)
-                                return 0;
-                        udelay(ACPI_EC_UDELAY);
-                } while (--i>0);
+                if (acpi_ec_read_status(ec) & ACPI_EC_FLAG_OBF)
+                        return_VALUE(0);
                 break;
+
         case ACPI_EC_EVENT_IBE:
-                do {
-                        acpi_hw_low_level_read(8, &acpi_ec_status, &ec->status_addr);
-                        if (!(acpi_ec_status & ACPI_EC_FLAG_IBF))
-                                return 0;
-                        udelay(ACPI_EC_UDELAY);
-                } while (--i>0);
+                if (~acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF)
+                        return_VALUE(0);
                 break;
-        default:
-                return -EINVAL;
         }
 
-        return -ETIME;
+        return_VALUE(-ETIME);
 }
 
 
+
+static int
+acpi_ec_enter_burst_mode (
+        struct acpi_ec          *ec)
+{
+        u32                     tmp = 0;
+        int                     status = 0;
+
+        ACPI_FUNCTION_TRACE("acpi_ec_enter_burst_mode");
+
+        status = acpi_ec_read_status(ec);
+        if (status != -EINVAL &&
+                !(status & ACPI_EC_FLAG_BURST)){
+                ACPI_DEBUG_PRINT((ACPI_DB_INFO,"entering burst mode \n"));
+                acpi_hw_low_level_write(8, ACPI_EC_BURST_ENABLE, &ec->command_addr);
+                status = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
+                if (status){
+                        acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+                        ACPI_DEBUG_PRINT((ACPI_DB_ERROR," status = %d\n", status));
+                        return_VALUE(-EINVAL);
+                }
+                acpi_hw_low_level_read(8, &tmp, &ec->data_addr);
+                acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+                if(tmp != 0x90 ) {/* Burst ACK byte*/
+                        ACPI_DEBUG_PRINT((ACPI_DB_ERROR,"Ack failed \n"));
+                        return_VALUE(-EINVAL);
+                }
+        } else
+                ACPI_DEBUG_PRINT((ACPI_DB_INFO,"already be in burst mode \n"));
+        atomic_set(&ec->leaving_burst , 0);
+        return_VALUE(0);
+}
+
+static int
+acpi_ec_leave_burst_mode (
+        struct acpi_ec          *ec)
+{
+        int                     status =0;
+
+        ACPI_FUNCTION_TRACE("acpi_ec_leave_burst_mode");
+
+        atomic_set(&ec->leaving_burst , 1);
+        status = acpi_ec_read_status(ec);
+        if (status != -EINVAL &&
+                (status & ACPI_EC_FLAG_BURST)){
+                ACPI_DEBUG_PRINT((ACPI_DB_INFO,"leaving burst mode\n"));
+                acpi_hw_low_level_write(8, ACPI_EC_BURST_DISABLE, &ec->command_addr);
+                status = acpi_ec_wait(ec, ACPI_EC_FLAG_IBF);
+                if (status){
+                        acpi_enable_gpe(NULL, ec->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);
+                status = acpi_ec_read_status(ec);
+                if (status != -EINVAL &&
+                        (status & ACPI_EC_FLAG_BURST)) {
+                        ACPI_DEBUG_PRINT((ACPI_DB_ERROR,"------->status fail\n"));
+                        return_VALUE(-EINVAL);
+                }
+        }else
+                ACPI_DEBUG_PRINT((ACPI_DB_INFO,"already be in Non-burst mode \n"));
+        ACPI_DEBUG_PRINT((ACPI_DB_INFO,"leaving burst mode\n"));
+
+        return_VALUE(0);
+}
+
 static int
 acpi_ec_read (
         struct acpi_ec          *ec,
         u8                      address,
         u32                     *data)
 {
-        acpi_status             status = AE_OK;
-        int                     result = 0;
-        unsigned long           flags = 0;
-        u32                     glk = 0;
+        int                     status = 0;
+        u32                     glk;
 
         ACPI_FUNCTION_TRACE("acpi_ec_read");
 
         if (!ec || !data)
                 return_VALUE(-EINVAL);
 
+retry:
         *data = 0;
 
         if (ec->global_lock) {
@@ -160,32 +246,50 @@ acpi_ec_read (
                 if (ACPI_FAILURE(status))
                         return_VALUE(-ENODEV);
         }
-        
-        spin_lock_irqsave(&ec->lock, flags);
+
+        WARN_ON(in_interrupt());
+        down(&ec->sem);
+
+        if(acpi_ec_enter_burst_mode(ec))
+                goto end;
 
         acpi_hw_low_level_write(8, ACPI_EC_COMMAND_READ, &ec->command_addr);
-        result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
-        if (result)
+        status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
+        acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+        if (status) {
                 goto end;
+        }
 
         acpi_hw_low_level_write(8, address, &ec->data_addr);
-        result = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
-        if (result)
+        status= acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
+        if (status){
+                acpi_enable_gpe(NULL, ec->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_DEBUG_PRINT((ACPI_DB_INFO, "Read [%02x] from address [%02x]\n",
                 *data, address));
-
+        
 end:
-        spin_unlock_irqrestore(&ec->lock, flags);
+        acpi_ec_leave_burst_mode(ec);
+        up(&ec->sem);
 
         if (ec->global_lock)
                 acpi_release_global_lock(glk);
 
-        return_VALUE(result);
+        if(atomic_read(&ec->leaving_burst) == 2){
+                ACPI_DEBUG_PRINT((ACPI_DB_INFO,"aborted, retry ...\n"));
+                while(!atomic_read(&ec->pending_gpe)){
+                        msleep(1);      
+                }
+                acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+                goto retry;
+        }
+
+        return_VALUE(status);
 }
 
 
@@ -195,49 +299,80 @@ acpi_ec_write (
         u8                      address,
         u8                      data)
 {
-        int                     result = 0;
-        acpi_status             status = AE_OK;
-        unsigned long           flags = 0;
-        u32                     glk = 0;
+        int                     status = 0;
+        u32                     glk;
+        u32                     tmp;
 
         ACPI_FUNCTION_TRACE("acpi_ec_write");
 
         if (!ec)
                 return_VALUE(-EINVAL);
-
+retry:
         if (ec->global_lock) {
                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
                 if (ACPI_FAILURE(status))
                         return_VALUE(-ENODEV);
         }
 
-        spin_lock_irqsave(&ec->lock, flags);
+        WARN_ON(in_interrupt());
+        down(&ec->sem);
+
+        if(acpi_ec_enter_burst_mode(ec))
+                goto end;
+
+        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);
+                status = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
+                if (status)
+                        goto end;
+                acpi_hw_low_level_read(8, &tmp, &ec->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);
-        result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
-        if (result)
+        status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
+        acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+        if (status){
                 goto end;
+        }
 
         acpi_hw_low_level_write(8, address, &ec->data_addr);
-        result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
-        if (result)
+        status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
+        if (status){
+                acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
                 goto end;
+        }
 
         acpi_hw_low_level_write(8, data, &ec->data_addr);
-        result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
-        if (result)
+        status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
+        acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+        if (status)
                 goto end;
 
         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Wrote [%02x] to address [%02x]\n",
                 data, address));
 
 end:
-        spin_unlock_irqrestore(&ec->lock, flags);
+        acpi_ec_leave_burst_mode(ec);
+        up(&ec->sem);
 
         if (ec->global_lock)
                 acpi_release_global_lock(glk);
 
-        return_VALUE(result);
+        if(atomic_read(&ec->leaving_burst) == 2){
+                ACPI_DEBUG_PRINT((ACPI_DB_INFO,"aborted, retry ...\n"));
+                while(!atomic_read(&ec->pending_gpe)){
+                        msleep(1);      
+                }
+                acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+                goto retry;
+        }
+
+        return_VALUE(status);
 }
 
 /*
@@ -289,16 +424,14 @@ acpi_ec_query (
         struct acpi_ec          *ec,
         u32                     *data)
 {
-        int                     result = 0;
-        acpi_status             status = AE_OK;
-        unsigned long           flags = 0;
-        u32                     glk = 0;
+        int                     status = 0;
+        u32                     glk;
 
         ACPI_FUNCTION_TRACE("acpi_ec_query");
 
         if (!ec || !data)
                 return_VALUE(-EINVAL);
-
+retry:
         *data = 0;
 
         if (ec->global_lock) {
@@ -307,29 +440,43 @@ acpi_ec_query (
                         return_VALUE(-ENODEV);
         }
 
+        down(&ec->sem);
+        if(acpi_ec_enter_burst_mode(ec))
+                goto end;
         /*
          * 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->lock, flags);
-
         acpi_hw_low_level_write(8, ACPI_EC_COMMAND_QUERY, &ec->command_addr);
-        result = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
-        if (result)
+        status = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
+        if (status){
+                acpi_enable_gpe(NULL, ec->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);
         if (!*data)
-                result = -ENODATA;
+                status = -ENODATA;
 
 end:
-        spin_unlock_irqrestore(&ec->lock, flags);
+        acpi_ec_leave_burst_mode(ec);
+        up(&ec->sem);
 
         if (ec->global_lock)
                 acpi_release_global_lock(glk);
 
-        return_VALUE(result);
+        if(atomic_read(&ec->leaving_burst) == 2){
+                ACPI_DEBUG_PRINT((ACPI_DB_INFO,"aborted, retry ...\n"));
+                while(!atomic_read(&ec->pending_gpe)){
+                        msleep(1);      
+                }
+                acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+                goto retry;
+        }
+
+        return_VALUE(status);
 }
 
 
@@ -347,42 +494,29 @@ acpi_ec_gpe_query (
         void                    *ec_cxt)
 {
         struct acpi_ec          *ec = (struct acpi_ec *) ec_cxt;
-        u32                     value = 0;
-        unsigned long           flags = 0;
+        u32                     value;
+        int                     result = -ENODATA;
         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;       
+        if (acpi_ec_read_status(ec) & ACPI_EC_FLAG_SCI)
+                result = acpi_ec_query(ec, &value);
 
-        spin_lock_irqsave(&ec->lock, flags);
-        acpi_hw_low_level_read(8, &value, &ec->command_addr);
-        spin_unlock_irqrestore(&ec->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))
+        if (result)
                 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->handle, object_name, NULL, NULL);
-
-end:
-        acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+        atomic_dec(&ec->pending_gpe);
+end:    
+        return;
 }
 
 static u32
@@ -390,6 +524,7 @@ acpi_ec_gpe_handler (
         void                    *data)
 {
         acpi_status             status = AE_OK;
+        u32                     value;
         struct acpi_ec          *ec = (struct acpi_ec *) data;
 
         if (!ec)
@@ -397,13 +532,39 @@ acpi_ec_gpe_handler (
 
         acpi_disable_gpe(NULL, ec->gpe_bit, ACPI_ISR);
 
-        status = acpi_os_queue_for_execution(OSD_PRIORITY_GPE,
-                acpi_ec_gpe_query, ec);
+        value = acpi_ec_read_status(ec);
 
-        if (status == AE_OK)
-                return ACPI_INTERRUPT_HANDLED;
-        else
-                return ACPI_INTERRUPT_NOT_HANDLED;
+        if((value & ACPI_EC_FLAG_IBF) &&
+                !(value & ACPI_EC_FLAG_BURST) &&
+                        (atomic_read(&ec->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
+                                        and retry */
+                wake_up(&ec->wait);
+        }else {
+                if ((ec->expect_event == ACPI_EC_EVENT_OBF &&
+                                (value & ACPI_EC_FLAG_OBF)) ||
+                                (ec->expect_event == ACPI_EC_EVENT_IBE &&
+                                !(value & ACPI_EC_FLAG_IBF))) {
+                        ec->expect_event = 0;
+                        wake_up(&ec->wait);
+                        
+                }
+        }
+
+        if (value & ACPI_EC_FLAG_SCI){
+                atomic_add(1, &ec->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;
 }
 
 /* --------------------------------------------------------------------------
@@ -421,10 +582,8 @@ acpi_ec_space_setup (
          * The EC object is in the handler context and is needed
          * when calling the acpi_ec_space_handler.
          */
-        if(function == ACPI_REGION_DEACTIVATE) 
-                *return_context = NULL;
-        else 
-                *return_context = handler_context;
+        *return_context  = (function != ACPI_REGION_DEACTIVATE) ?
+                                                handler_context : NULL;
 
         return AE_OK;
 }
@@ -555,7 +714,7 @@ static int
 acpi_ec_add_fs (
         struct acpi_device      *device)
 {
-        struct proc_dir_entry   *entry = NULL;
+        struct proc_dir_entry   *entry;
 
         ACPI_FUNCTION_TRACE("acpi_ec_add_fs");
 
@@ -606,9 +765,9 @@ static int
 acpi_ec_add (
         struct acpi_device      *device)
 {
-        int                     result = 0;
-        acpi_status             status = AE_OK;
-        struct acpi_ec          *ec = NULL;
+        int                     result;
+        acpi_status             status;
+        struct acpi_ec          *ec;
         unsigned long           uid;
 
         ACPI_FUNCTION_TRACE("acpi_ec_add");
@@ -623,7 +782,10 @@ acpi_ec_add (
 
         ec->handle = device->handle;
         ec->uid = -1;
-        spin_lock_init(&ec->lock);
+        atomic_set(&ec->pending_gpe, 0);
+        atomic_set(&ec->leaving_burst , 1);
+        init_MUTEX(&ec->sem);
+        init_waitqueue_head(&ec->wait);
         strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
         strcpy(acpi_device_class(device), ACPI_EC_CLASS);
         acpi_driver_data(device) = ec;
@@ -637,7 +799,7 @@ acpi_ec_add (
         if (ec_ecdt && ec_ecdt->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);
 
                 kfree(ec_ecdt);
@@ -677,7 +839,7 @@ acpi_ec_remove (
         struct acpi_device      *device,
         int                     type)
 {
-        struct acpi_ec          *ec = NULL;
+        struct acpi_ec          *ec;
 
         ACPI_FUNCTION_TRACE("acpi_ec_remove");
 
@@ -732,8 +894,8 @@ static int
 acpi_ec_start (
         struct acpi_device      *device)
 {
-        acpi_status             status = AE_OK;
-        struct acpi_ec          *ec = NULL;
+        acpi_status             status;
+        struct acpi_ec          *ec;
 
         ACPI_FUNCTION_TRACE("acpi_ec_start");
 
@@ -789,8 +951,8 @@ acpi_ec_stop (
         struct acpi_device      *device,
         int                     type)
 {
-        acpi_status             status = AE_OK;
-        struct acpi_ec          *ec = NULL;
+        acpi_status             status;
+        struct acpi_ec          *ec;
 
         ACPI_FUNCTION_TRACE("acpi_ec_stop");
 
@@ -832,7 +994,6 @@ acpi_fake_ecdt_callback (
         status = acpi_evaluate_integer(handle, "_GPE", NULL, &ec_ecdt->gpe_bit);
         if (ACPI_FAILURE(status))
                 return status;
-        spin_lock_init(&ec_ecdt->lock);
         ec_ecdt->global_lock = TRUE;
         ec_ecdt->handle = handle;
 
@@ -890,7 +1051,7 @@ acpi_ec_get_real_ecdt(void)
         acpi_status             status;
         struct acpi_table_ecdt  *ecdt_ptr;
 
-        status = acpi_get_firmware_table("ECDT", 1, ACPI_LOGICAL_ADDRESSING, 
+        status = acpi_get_firmware_table("ECDT", 1, ACPI_LOGICAL_ADDRESSING,
                 (struct acpi_table_header **) &ecdt_ptr);
         if (ACPI_FAILURE(status))
                 return -ENODEV;
@@ -905,11 +1066,12 @@ acpi_ec_get_real_ecdt(void)
                 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;
-        spin_lock_init(&ec_ecdt->lock);
         /* use the GL just to be safe */
         ec_ecdt->global_lock = TRUE;
         ec_ecdt->uid = ecdt_ptr->uid;
@@ -978,7 +1140,7 @@ error:
 
 static int __init acpi_ec_init (void)
 {
-        int                     result = 0;
+        int                     result;
 
         ACPI_FUNCTION_TRACE("acpi_ec_init");