Re: [patch 2/2] acpi: Avoid dropping rapid hotkey events (or other GPEs) on Asus EeePC

[Alan Jenkins <alan-jenkins@tuffmail.co.uk>]

Alan Jenkins wrote:
> Alexey Starikovskiy wrote:
>   
>> Hi Alan,
>> That patch is old news already...
>> There is a new shiny one appended to 9998/10724/11549...
>> Please give it a try. It does disable GPE, but for very small duration.
>>     
>
> Ok.  I was put off by the noise :-).
>
> I've just tested 2.6.27-rc6 with
> <http://bugzilla.kernel.org/show_bug.cgi?id=9998#c81>.  It still "drops"
> some events, but now it takes longer to happen.  I have to work much
> harder bashing the keys to reproduce it.
>
>
> Like before, missing an event has severe consequences.  The missed event
> is buffered.  When a new event occurs, only the oldest event is removed
> from the buffer.  Therefore the buffer can only grow.  Eventually,
> something breaks.  Events stop being delivered altogether; presumably
> the buffer overflows.  I confirmed that this does still happen.
>
> Remember that these are the consequences of a specific EC bug.  On my
> EC, querying an event always clears SCI_EVT, even if there are more
> events pending.  It is only re-raised when a new event fires.
>
>
> I'll try reading the patch.  I may try capturing an EC debug log to show
> how the event is dropped, but that will take time.
>   

Ok, I think I've isolated the problem to a specific change.  It's our
good friend EC_FLAGS_QUERY_PENDING again.

Your new patch clears the pending flag after the query transaction has
finished.  Previously, it was cleared as soon as the query command was
initiated.

I hacked it back and it works.  Was there a specific reason for the change?

Regards
Alan

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index 97168d4..2078cff 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -262,6 +262,8 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec, u8 command,
 	ec->t.rlen = rdata_len;
 	/* start transaction */
 	acpi_ec_write_cmd(ec, command);
+	if (command == ACPI_EC_COMMAND_QUERY)
+		clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
 	/* if we selected poll mode or failed in GPE-mode do a poll loop */
 	if (force_poll ||
 	    !test_bit(EC_FLAGS_GPE_MODE, &ec->flags) ||
@@ -453,7 +455,6 @@ static int acpi_ec_query(struct acpi_ec *ec, u8 * data)
 	 */
 
 	result = acpi_ec_transaction(ec, ACPI_EC_COMMAND_QUERY, NULL, 0, &d, 1, 0);
-	clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
 	if (result)
 		return result;