Fwd: [PATCH RFC] x86: hpet: Avoid the readback penalty

From: John Drescher
Date: Thu Sep 16 2010 - 00:45:17 EST


On Wed, Sep 15, 2010 at 9:54 AM, John Drescher <drescherjm@xxxxxxxxx> wrote:
> On Wed, Sep 15, 2010 at 9:11 AM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>> On Tue, 14 Sep 2010, tip-bot for Thomas Gleixner wrote:
>>> x86: hpet: Work around hardware stupidity
>>
>> After my brain recovered from yesterdays exposure with the x86 timer
>> horror, I came up with a different solution for this problem, which
>> avoids the readback of the compare register completely. It works
>> nicely on my affected ATI system, but needs some exposure to the other
>> machines.
>>
>> Comments ?
>>
>
> I can test this on my i7 machine in tonight (around 12 hours from now).

Seems to work fine on my i7 box. I applied the first patch to
2.6.36-rc4-git2 then after that I applied the new patch from this
email. Both patches applied cleanly and I am now running the patched
kernel without any issue. I turned off the clocksource=acpi_pm
workaround I had enabled from the original problem.

jmd1 ~ # uname -a
Linux jmd1 2.6.36-rc4-git2-no-penalty #3 SMP PREEMPT Wed Sep 15
21:25:53 EDT 2010 x86_64 Intel(R) Core(TM) i7 CPU 920 @ 2.67GHz
GenuineIntel GNU/Linux

John



--
John M. Drescher
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