Bug#494546: hotkeys in 2.6.26 (was: No boot without ac adapter ...)

[Eric Cooper <ecc@cmu.edu>]

On Sat, Aug 16, 2008 at 12:15:03PM +0300, Damyan Ivanov wrote:
> what is more interesting is if hotkeys still work after bringing 
> volume to min and then to max (with them).

This is bug #494546 that you posted about earlier, right?

The thermal workaround has no affect on it.  I can confirm that

  1. the hotkeys still stop working after rapid, repeated use in the
     stock Debian 2.6.26 kernel

  2. the referenced patch fixes the problem (also attached here for
     convenience)

-- 
Eric Cooper             e c c @ c m u . e d u

This fixes a regression in 2.6.26 (from 2.6.25.3).  Initially reported as
"Asus Eee PC hotkeys stop working if pressed quickly" in bugzilla
<http://bugzilla.kernel.org/show_bug.cgi?id=11089>.

The regression was caused by a recently added check for interrupt storms.
The Eee PC triggers this check and switches to polling.  When multiple events
arrive between polling intervals, only one is fetched from the EC.  This causes
erroneous behaviour; ultimately events stop being delivered altogether when the
EC buffer overflows.

Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>

---
diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index 5622aee..2b4c5a2 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -459,14 +459,10 @@ void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
 
 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
 
-static void acpi_ec_gpe_query(void *ec_cxt)
+static void acpi_ec_gpe_run_handler(struct acpi_ec *ec, u8 value)
 {
-	struct acpi_ec *ec = ec_cxt;
-	u8 value = 0;
 	struct acpi_ec_query_handler *handler, copy;
 
-	if (!ec || acpi_ec_query(ec, &value))
-		return;
 	mutex_lock(&ec->lock);
 	list_for_each_entry(handler, &ec->list, node) {
 		if (value == handler->query_bit) {
@@ -484,6 +480,18 @@ static void acpi_ec_gpe_query(void *ec_cxt)
 	mutex_unlock(&ec->lock);
 }
 
+static void acpi_ec_gpe_query(void *ec_cxt)
+{
+	struct acpi_ec *ec = ec_cxt;
+	u8 value = 0;
+
+	if (!ec)
+		return;
+
+	while (!acpi_ec_query(ec, &value))
+		acpi_ec_gpe_run_handler(ec, value);
+}
+
 static u32 acpi_ec_gpe_handler(void *data)
 {
 	acpi_status status = AE_OK;