From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm@linux-foundation.org Subject: [patch 3/5] ACPI: EC: Don't degrade to poll mode at storm automatically Date: Mon, 22 Sep 2008 14:37:32 -0700 Message-ID: <200809222137.m8MLbXl5031009@imap1.linux-foundation.org> Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:59596 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753230AbYIVVik (ORCPT ); Mon, 22 Sep 2008 17:38:40 -0400 Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: lenb@kernel.org Cc: linux-acpi@vger.kernel.org, akpm@linux-foundation.org, astarikovskiy@suse.de, andi@firstfloor.org, hmh@hmh.eng.br, maxi@daemonizer.de, stable@kernel.org From: Alexey Starikovskiy Not all users of semi-broken EC devices want to degrade to poll mode, so give them right to choose. 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: Alexey Starikovskiy Cc: Alexey Starikovskiy Cc: Maximilian Engelhardt Cc: Henrique de Moraes Holschuh Cc: Andi Kleen Cc: Signed-off-by: Andrew Morton --- Documentation/kernel-parameters.txt | 5 +++ drivers/acpi/ec.c | 36 ++++++++++++++++++-------- 2 files changed, 31 insertions(+), 10 deletions(-) diff -puN Documentation/kernel-parameters.txt~acpi-ec-dont-degrade-to-poll-mode-at-storm-automatically Documentation/kernel-parameters.txt --- a/Documentation/kernel-parameters.txt~acpi-ec-dont-degrade-to-poll-mode-at-storm-automatically +++ a/Documentation/kernel-parameters.txt @@ -736,6 +736,11 @@ and is between 256 and 4096 characters. eata= [HW,SCSI] + ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode + Format: + 0: polling mode + non-0: interrupt mode (default) + edd= [EDD] Format: {"off" | "on" | "skip[mbr]"} diff -puN drivers/acpi/ec.c~acpi-ec-dont-degrade-to-poll-mode-at-storm-automatically drivers/acpi/ec.c --- a/drivers/acpi/ec.c~acpi-ec-dont-degrade-to-poll-mode-at-storm-automatically +++ a/drivers/acpi/ec.c @@ -110,6 +110,8 @@ static struct acpi_ec { u8 handlers_installed; } *boot_ec, *first_ec; +int acpi_ec_intr = 1; /* Default is interrupt mode */ + /* * Some Asus system have exchanged ECDT data/command IO addresses. */ @@ -516,12 +518,14 @@ static u32 acpi_ec_gpe_handler(void *dat acpi_status status = AE_OK; struct acpi_ec *ec = data; u8 state = acpi_ec_read_status(ec); + static bool warn_done = false; pr_debug(PREFIX "~~~> interrupt\n"); atomic_inc(&ec->irq_count); - if (atomic_read(&ec->irq_count) > 5) { - pr_err(PREFIX "GPE storm detected, disabling EC GPE\n"); - ec_switch_to_poll_mode(ec); + if (!warn_done && atomic_read(&ec->irq_count) > 5) { + pr_warning(PREFIX "GPE storm detected, try to use ec_intr=0 " + "kernel option, if you see problems with keyboard.\n"); + warn_done = 1; goto end; } clear_bit(EC_FLAGS_WAIT_GPE, &ec->flags); @@ -848,20 +852,21 @@ static int ec_install_handlers(struct ac acpi_status status; if (ec->handlers_installed) return 0; - status = acpi_install_gpe_handler(NULL, ec->gpe, + if (acpi_ec_intr) { + status = acpi_install_gpe_handler(NULL, ec->gpe, ACPI_GPE_EDGE_TRIGGERED, &acpi_ec_gpe_handler, ec); - if (ACPI_FAILURE(status)) - return -ENODEV; - - acpi_set_gpe_type(NULL, ec->gpe, ACPI_GPE_TYPE_RUNTIME); - acpi_enable_gpe(NULL, ec->gpe, ACPI_NOT_ISR); + if (ACPI_FAILURE(status)) + return -ENODEV; + acpi_set_gpe_type(NULL, ec->gpe, ACPI_GPE_TYPE_RUNTIME); + acpi_enable_gpe(NULL, ec->gpe, ACPI_NOT_ISR); + } status = acpi_install_address_space_handler(ec->handle, ACPI_ADR_SPACE_EC, &acpi_ec_space_handler, NULL, ec); - if (ACPI_FAILURE(status)) { + if (ACPI_FAILURE(status) && acpi_ec_intr) { acpi_remove_gpe_handler(NULL, ec->gpe, &acpi_ec_gpe_handler); return -ENODEV; } @@ -1047,3 +1052,14 @@ static void __exit acpi_ec_exit(void) return; } #endif /* 0 */ + +static int __init acpi_ec_set_intr_mode(char *str) +{ + if (!get_option(&str, &acpi_ec_intr)) { + acpi_ec_intr = 0; + return 0; + } + return 1; +} + +__setup("ec_intr=", acpi_ec_set_intr_mode); _