Messages in this thread Patch in this message |  | | Date | Sun, 7 Jun 2009 12:05:41 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH v2] acpi: Fix regression where _PPC is not read at boot even when ignore_ppc=0 |
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* Darrick J. Wong <djwong@us.ibm.com> wrote:
> On Fri, May 15, 2009 at 12:12:19PM -0700, Darrick J. Wong wrote: > > On Thu, Apr 30, 2009 at 12:13:38PM +0100, Matthew Garrett wrote: > > > On Thu, Apr 30, 2009 at 01:10:42PM +0200, Ingo Molnar wrote: > > > > > > > thanks - i've applied this and started testing it. I suspect 1-2 > > > > days of test-time should be enough to see if it breaks this box in > > > > any way. > > > > > > My recollection was that you'd see the machine limited to 1GHz on every > > > boot? > > > > That seems accurate based on my reading of the old thread. > > > > It's been a couple of weeks; has anyone seen any problems? > > Now it's been thirty days since I last heard from anyone. Has the > problem been fixed by some other means?
I see no problems on that system here, with the patch below applied. So, as i indicated above, feel free to pursue this angle, there's no objection from me.
Thanks,
Ingo
-------------> From 244b66ac1fbbe25262a9bcc28179e50930290de8 Mon Sep 17 00:00:00 2001 From: Matthew Garrett <mjg59@srcf.ucam.org> Date: Thu, 30 Apr 2009 10:54:14 +0100 Subject: [PATCH] acpi: Fix regression where _PPC is not read at boot even when ignore_ppc=0
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.
This second version restores the correct function call, which simplifies the patch. I apologize for the churn and the poor eyesight.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com> Cc: "Darrick J. Wong" <djwong@us.ibm.com> Cc: Thomas Renninger <trenn@suse.de> LKML-Reference: <20090430095414.GA19462@srcf.ucam.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> --- 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 cafb410..85af717 100644 --- a/drivers/acpi/processor_perflib.c +++ b/drivers/acpi/processor_perflib.c @@ -348,7 +348,11 @@ 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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