From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm@linux-foundation.org Subject: [patch 2/2] acpi: Avoid dropping rapid hotkey events (or other GPEs) on Asus EeePC Date: Wed, 20 Aug 2008 16:41:47 -0700 Message-ID: <200808202341.m7KNflv7005413@imap1.linux-foundation.org> Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:39209 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751471AbYHTXml (ORCPT ); Wed, 20 Aug 2008 19:42:41 -0400 Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: andi@firstfloor.org Cc: linux-acpi@vger.kernel.org, akpm@linux-foundation.org, alan-jenkins@tuffmail.co.uk, astarikovskiy@suse.de, hmh@hmh.eng.br, maxi@daemonizer.de, stable@kernel.org From: Alan Jenkins It looks like this EC clears the SMI_EVT bit after every query, even if there are more events pending. The workaround is to repeatedly query the EC until it reports that no events remain. 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 . 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 Cc: Alexey Starikovskiy Cc: Maximilian Engelhardt Cc: Henrique de Moraes Holschuh Cc: Andi Kleen Cc: Signed-off-by: Andrew Morton --- drivers/acpi/ec.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff -puN drivers/acpi/ec.c~acpi-avoid-dropping-rapid-hotkey-events-or-other-gpes-on-asus-eeepc drivers/acpi/ec.c --- a/drivers/acpi/ec.c~acpi-avoid-dropping-rapid-hotkey-events-or-other-gpes-on-asus-eeepc +++ a/drivers/acpi/ec.c @@ -486,14 +486,10 @@ void acpi_ec_remove_query_handler(struct 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) { @@ -511,6 +507,18 @@ static void acpi_ec_gpe_query(void *ec_c 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; _