From 2a908002c7b1b666616103e9df2419b38d7c6f1f Mon Sep 17 00:00:00 2001 From: Frans Pop Date: Wed, 26 Aug 2009 14:29:29 -0700 Subject: ACPI processor: force throttling state when BIOS returns incorrect value If the BIOS reports an invalid throttling state (which seems to be fairly common after system boot), a reset is done to state T0. Because of a check in acpi_processor_get_throttling_ptc(), the reset never actually gets executed, which results in the error reoccurring on every access of for example /proc/acpi/processor/CPU0/throttling. Add a 'force' option to acpi_processor_set_throttling() to ensure the reset really takes effect. Addresses http://bugzilla.kernel.org/show_bug.cgi?id=13389 This patch, together with the next one, fixes a regression introduced in 2.6.30, listed on the regression list. They have been available for 2.5 months now in bugzilla, but have not been picked up, despite various reminders and without any reason given. Google shows that numerous people are hitting this issue. The issue is in itself relatively minor, but the bug in the code is clear. The patches have been in all my kernels and today testing has shown that throttling works correctly with the patches applied when the system overheats (http://bugzilla.kernel.org/show_bug.cgi?id=13918#c14). Signed-off-by: Frans Pop Acked-by: Zhang Rui Cc: Len Brown Cc: "Rafael J. Wysocki" Cc: Rusty Russell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/acpi/processor_thermal.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers/acpi/processor_thermal.c') diff --git a/drivers/acpi/processor_thermal.c b/drivers/acpi/processor_thermal.c index 39838c66603..31adda1099e 100644 --- a/drivers/acpi/processor_thermal.c +++ b/drivers/acpi/processor_thermal.c @@ -66,7 +66,7 @@ static int acpi_processor_apply_limit(struct acpi_processor *pr) if (pr->limit.thermal.tx > tx) tx = pr->limit.thermal.tx; - result = acpi_processor_set_throttling(pr, tx); + result = acpi_processor_set_throttling(pr, tx, false); if (result) goto end; } @@ -421,12 +421,12 @@ processor_set_cur_state(struct thermal_cooling_device *cdev, if (state <= max_pstate) { if (pr->flags.throttling && pr->throttling.state) - result = acpi_processor_set_throttling(pr, 0); + result = acpi_processor_set_throttling(pr, 0, false); cpufreq_set_cur_state(pr->id, state); } else { cpufreq_set_cur_state(pr->id, max_pstate); result = acpi_processor_set_throttling(pr, - state - max_pstate); + state - max_pstate, false); } return result; } -- cgit v1.2.3-18-g5258