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ACPI: Fix regression where _PPC is not read at boot even when ignore_ppc=0

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Earlier, Ingo Molnar posted a patch to make it so that the kernel would avoid
reading _PPC on his broken T60.  Unfortunately, it seems that with Thomas
Renninger's patch last July to eliminate _PPC evaluations when the processor
driver loads, the kernel never actually reads _PPC at all!  This is problematic
if you happen to boot your non-T60 computer in a state where the BIOS _wants_
_PPC to be something other than zero.

So, put the _PPC evaluation back into acpi_processor_get_performance_info if
ignore_ppc isn't 1.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Darrick J. Wong 2010-02-18 10:28:20 -08:00 committed by Len Brown
parent f8b55f2510
commit 455c0d71d4
1 changed files with 5 additions and 1 deletions
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6
drivers/acpi/processor_perflib.c
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@ -413,7 +413,11 @@ static int acpi_processor_get_performance_info(struct acpi_processor *pr)
if (result)
goto update_bios;
return 0;
/* We need to call _PPC once when cpufreq starts */
if (ignore_ppc != 1)
result = acpi_processor_get_platform_limit(pr);
return result;
/*
* Having _PPC but missing frequencies (_PSS, _PCT) is a very good hint that