From: Youquan, Song <youquan.song@xxxxxxxxx> When cpu frequencey scaling is disabled, some BIOSes report _PSS with all 0x80000000. If the kernel treats this case as valid, the kernel will boot crash when load cpufreq govenors. So in order to cover more buggy BIOSs, the patch just check _PSS core frequency invalidation. On Sun, 15 Mar 2009 23:22:37 -0400 (EDT) Len Brown <lenb@xxxxxxxxxx> wrote: > NAK -- per previous discussion on the list. > > This patch is not the right way to address this issue, > which is reported here, BTW: > > https://bugzilla.redhat.com/show_bug.cgi?id=467941 Signed-off-by: Youquan, Song <youquan.song@xxxxxxxxx> Signed-off-by: Pallipadi, Venkatesh <venkatesh.pallipadi@xxxxxxxxx> Cc: Len Brown <lenb@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/acpi/processor_perflib.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff -puN drivers/acpi/processor_perflib.c~acpi-check-_pss-invalidation-when-bios-report-_pss-with-all-0x80000000 drivers/acpi/processor_perflib.c --- a/drivers/acpi/processor_perflib.c~acpi-check-_pss-invalidation-when-bios-report-_pss-with-all-0x80000000 +++ a/drivers/acpi/processor_perflib.c @@ -42,6 +42,7 @@ #define ACPI_PROCESSOR_CLASS "processor" #define ACPI_PROCESSOR_FILE_PERFORMANCE "performance" #define _COMPONENT ACPI_PROCESSOR_COMPONENT +#define ACPI_PROCESSOR_PSS_INVALID 0x80000000 ACPI_MODULE_NAME("processor_perflib"); static DEFINE_MUTEX(performance_mutex); @@ -316,6 +317,14 @@ static int acpi_processor_get_performanc kfree(pr->performance->states); goto end; } + + if (px->core_frequency == ACPI_PROCESSOR_PSS_INVALID) { + printk(KERN_ERR PREFIX + "P-states disabled in the BIOS\n"); + result = -EFAULT; + kfree(pr->performance->states); + goto end; + } } end: _ -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
