diff mbox

[2/8] acpi: check _PSS invalidation when BIOS report _PSS with 0x80000000

Message ID 200903041955.n24JtPSM027990@imap1.linux-foundation.org (mailing list archive)
State Rejected, archived
Headers show

Commit Message

Andrew Morton March 4, 2009, 7:55 p.m. UTC
From: Youquan, Song <youquan.song@intel.com>

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.

Signed-off-by: Youquan, Song <youquan.song@intel.com>
Signed-off-by: Pallipadi, Venkatesh <venkatesh.pallipadi@intel.com>
Cc: Len Brown <lenb@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/acpi/processor_perflib.c |    9 +++++++++
 1 file changed, 9 insertions(+)

Comments

Len Brown March 16, 2009, 3:22 a.m. UTC | #1
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
--
Len Brown, Intel Open Source Technology Center

On Wed, 4 Mar 2009, akpm@linux-foundation.org wrote:

> From: Youquan, Song <youquan.song@intel.com>
> 
> 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.
> 
> Signed-off-by: Youquan, Song <youquan.song@intel.com>
> Signed-off-by: Pallipadi, Venkatesh <venkatesh.pallipadi@intel.com>
> Cc: Len Brown <lenb@kernel.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
> 
>  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:
> _
> 
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diff mbox

Patch

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: