ACPI: EC: auto select interrupt mode

Start in POLL mode, and if we receive confirmation GPE,
switch to INT mode.
If confirmations are not sent, switch back to POLL.

Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>

2 files changed, 16 insertions, 40 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index a13d69b2217d..727cc08f0f3b 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -586,11 +586,6 @@ and is between 256 and 4096 characters. It is defined in the file
 
         eata=           [HW,SCSI]
 
-        ec_intr=        [HW,ACPI] ACPI Embedded Controller interrupt mode
-                        Format: <int>
-                        0: polling mode
-                        non-0: interrupt mode (default)
-
         edd=            [EDD]
                         Format: {"of[f]" | "sk[ipmbr]"}
                         See comment in arch/i386/boot/edd.S
diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index 5ce90ce22b58..50d55fe71a30 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -71,14 +71,10 @@ enum ec_event {
 #define ACPI_EC_DELAY           500     /* Wait 500ms max. during EC ops */
 #define ACPI_EC_UDELAY_GLK      1000    /* Wait 1ms max. to get global lock */
 
-static enum ec_mode {
-        EC_INTR = 1,            /* Output buffer full */
-        EC_POLL,                /* Input buffer empty */
-} acpi_ec_mode = EC_INTR;
-
 enum {
         EC_FLAGS_WAIT_GPE = 0,          /* Don't check status until GPE arrives */
         EC_FLAGS_QUERY_PENDING,         /* Query is pending */
+        EC_FLAGS_GPE_MODE,              /* Expect GPE to be sent for status change */
 };
 
 static int acpi_ec_remove(struct acpi_device *device, int type);
@@ -169,21 +165,23 @@ static inline int acpi_ec_check_status(struct acpi_ec *ec, enum ec_event event)
 
 static int acpi_ec_wait(struct acpi_ec *ec, enum ec_event event, int force_poll)
 {
-        if (unlikely(force_poll) || acpi_ec_mode == EC_POLL) {
-                unsigned long delay = jiffies + msecs_to_jiffies(ACPI_EC_DELAY);
-                clear_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
-                while (time_before(jiffies, delay)) {
-                        if (acpi_ec_check_status(ec, event))
-                                return 0;
-                }
-        } else {
+        if (likely(test_bit(EC_FLAGS_GPE_MODE, &ec->flags)) &&
+            likely(!force_poll)) {
                 if (wait_event_timeout(ec->wait, acpi_ec_check_status(ec, event),
                                        msecs_to_jiffies(ACPI_EC_DELAY)))
                         return 0;
                 clear_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
                 if (acpi_ec_check_status(ec, event)) {
+                        clear_bit(EC_FLAGS_GPE_MODE, &ec->flags);
                         return 0;
                 }
+        } else {
+                unsigned long delay = jiffies + msecs_to_jiffies(ACPI_EC_DELAY);
+                clear_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
+                while (time_before(jiffies, delay)) {
+                        if (acpi_ec_check_status(ec, event))
+                                return 0;
+                }
         }
         printk(KERN_ERR PREFIX "acpi_ec_wait timeout,"
                                " status = %d, expect_event = %d\n",
@@ -481,18 +479,17 @@ static u32 acpi_ec_gpe_handler(void *data)
         struct acpi_ec *ec = data;
 
         clear_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
-
-        if (acpi_ec_mode == EC_INTR) {
+        if (test_bit(EC_FLAGS_GPE_MODE, &ec->flags))
                 wake_up(&ec->wait);
-        }
 
         if (acpi_ec_read_status(ec) & ACPI_EC_FLAG_SCI) {
                 if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
                         status = acpi_os_execute(OSL_EC_BURST_HANDLER,
                                 acpi_ec_gpe_query, ec);
-        }
+        } else if (unlikely(!test_bit(EC_FLAGS_GPE_MODE, &ec->flags)))
+                set_bit(EC_FLAGS_GPE_MODE, &ec->flags);
 
-        return status == AE_OK ?
+        return ACPI_SUCCESS(status) ?
             ACPI_INTERRUPT_HANDLED : ACPI_INTERRUPT_NOT_HANDLED;
 }
 
@@ -923,20 +920,4 @@ static void __exit acpi_ec_exit(void)
 
         return;
 }
-#endif                          /* 0 */
-
-static int __init acpi_ec_set_intr_mode(char *str)
-{
-        int intr;
-
-        if (!get_option(&str, &intr))
-                return 0;
-
-        acpi_ec_mode = (intr) ? EC_INTR : EC_POLL;
-
-        printk(KERN_NOTICE PREFIX "%s mode.\n", intr ? "interrupt" : "polling");
-
-        return 1;
-}
-
-__setup("ec_intr=", acpi_ec_set_intr_mode);
+#endif  /* 0 */