From: Andrew Morton <akpm@linux-foundation.org>
To: youquan_song@linux.intel.com
Cc: linux-acpi@vger.kernel.org, venkatesh.pallipadi@intel.com,
len.brown@intel.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ACPI: Check _PSS invalidation when BIOS report _PSS with all 0x80000000
Date: Fri, 21 Nov 2008 15:08:39 -0800 [thread overview]
Message-ID: <20081121150839.58dbedfa.akpm@linux-foundation.org> (raw)
In-Reply-To: <3606.172.16.183.72.1227236916.squirrel@linux.intel.com>
On Thu, 20 Nov 2008 19:08:36 -0800 (PST)
youquan_song@linux.intel.com wrote:
> Subject: Check _PSS invalidation when BIOS report _PSS with 0x80000000
>
> When cpu frequencey scaling disable,some BIOS report _PSS with all
> 0x80000000.
> If kernel treat 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
> frequencey invalidtion.
>
It's unclear how many machines this will affect, and what the effects
of not having the patch are upon those machines. That is useful
information for people who are deciding whcih kernel versions this
patch should be merged into.
Do you think this fix is needed in 2.6.28? 2.6.27.x? 2.6.26.x? etc?
>
> --- linux-2.6-tip-orignal/drivers/acpi/processor_perflib.c 2008-11-20
> 12:25:05.000000000 -0500
> +++ linux-2.6-tip/drivers/acpi/processor_perflib.c 2008-11-20
> 12:23:57.000000000 -0500
Your email client is wordwrapping the text, btw.
> @@ -50,6 +50,7 @@
> #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);
> @@ -324,6 +325,14 @@
> 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:
next prev parent reply other threads:[~2008-11-21 23:08 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-21 3:08 [PATCH] ACPI: Check _PSS invalidation when BIOS report _PSS with all 0x80000000 youquan_song
2008-11-21 3:08 ` youquan_song
2008-11-21 23:08 ` Andrew Morton [this message]
2008-11-24 23:02 ` Youquan,Song
2008-12-12 5:36 ` Len Brown
2009-03-12 13:22 ` Woody Suwalski
2009-03-13 2:16 ` Zhang Rui
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