From: Thomas Renninger Date: Sat, 19 May 2007 02:59:28 +0000 (-0500) Subject: ACPI: add "processor.ignore_ppc" hook to workaround BIOS _PPC weirdness X-Git-Tag: v2.6.25-rc1~297^2~11^2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=623b78c39c4525731f852072edd742cc4fba6786;p=platform%2Fkernel%2Flinux-stable.git ACPI: add "processor.ignore_ppc" hook to workaround BIOS _PPC weirdness There have been fixes using _PPC, which seem to unhide a problem on HP nx6125 (double cpufreq switch freezes the machine for several seconds). This one should provide a workaround for the nx6125 and for possible other machines that show any weird _PPC behaviour. Signed-off-by: Thomas Renninger Signed-off-by: Len Brown --- diff --git a/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c index 463b024..f32010b 100644 --- a/drivers/acpi/processor_perflib.c +++ b/drivers/acpi/processor_perflib.c @@ -60,6 +60,11 @@ static DEFINE_MUTEX(performance_mutex); * policy is adjusted accordingly. */ +static unsigned int ignore_ppc = 0; +module_param(ignore_ppc, uint, 0644); +MODULE_PARM_DESC(ignore_ppc, "If the frequency of your machine gets wrongly" \ + "limited by BIOS, this should help"); + #define PPC_REGISTERED 1 #define PPC_IN_USE 2 @@ -72,6 +77,9 @@ static int acpi_processor_ppc_notifier(struct notifier_block *nb, struct acpi_processor *pr; unsigned int ppc = 0; + if (ignore_ppc) + return 0; + mutex_lock(&performance_mutex); if (event != CPUFREQ_INCOMPATIBLE) @@ -130,7 +138,13 @@ static int acpi_processor_get_platform_limit(struct acpi_processor *pr) int acpi_processor_ppc_has_changed(struct acpi_processor *pr) { - int ret = acpi_processor_get_platform_limit(pr); + int ret; + + if (ignore_ppc) + return 0; + + ret = acpi_processor_get_platform_limit(pr); + if (ret < 0) return (ret); else