Messages in this thread Patch in this message | | | Date | Thu, 18 Feb 2010 10:28:20 -0800 | From | "Darrick J. Wong" <> | Subject | Re: [PATCH v2] acpi: Fix regression where _PPC is not read at boot even when ignore_ppc=0 |
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On Thu, Feb 18, 2010 at 04:02:39AM -0500, Len Brown wrote: > > On Tue, Feb 16, 2010 at 10:07:07PM +0000, Matthew Garrett wrote: > > > Did this ever get picked up? > > > > Nope. I vaguely recall asking a few times if there were any objections left, > > but there weren't any, and I think Len or someone said it looked good back at > > LPC last summer. Does not appear in 2.6.33-rc8 though. > > does it have a bugzilla entry? (as regressions tend to, thanks to rafael) > I don't see this in my mailbox anymore.
Nope, no bugzilla entry. Do I need to create one now? A patch resend follows.
--D
--- 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> ---
drivers/acpi/processor_perflib.c | 6 +++++- 1 files changed, 5 insertions(+), 1 deletions(-)
diff --git a/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c index 2cabadc..a959f6a 100644 --- a/drivers/acpi/processor_perflib.c +++ b/drivers/acpi/processor_perflib.c @@ -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
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