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From: Tim Gardner <tim.gardner@canonical.com>
To: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: MCP limit log messages, 2.6.36-rc4
Date: Fri, 24 Sep 2010 06:46:45 +0800	[thread overview]
Message-ID: <4C9BD8D5.7080201@canonical.com> (raw)
In-Reply-To: <20100923145428.4805adcb@jbarnes-desktop>

On 09/24/2010 05:54 AM, Jesse Barnes wrote:
> On Thu, 23 Sep 2010 13:48:16 -0700
> Jesse Barnes<jbarnes@virtuousgeek.org>  wrote:
>
>> On Wed, 15 Sep 2010 11:47:45 -0600
>> Tim Gardner<tim.gardner@canonical.com>  wrote:
>>
>>> I've been getting regular MCP limit log messages on a Dell Studio 1458
>>> (i5 CPU) with an A02 BIOS. With the attached debug hack it prints the
>>> following values:
>>>
>>> [   33.605098] intel ips 0000:00:1f.6: MCP limit exceeded: Avg power
>>> 30123, limit 1023
>>> [   38.597998] intel ips 0000:00:1f.6: MCP limit exceeded: Avg power
>>> 21697, limit 1023
>>> [   43.590917] intel ips 0000:00:1f.6: MCP limit exceeded: Avg power
>>> 15390, limit 1023
>>> [   48.583821] intel ips 0000:00:1f.6: MCP limit exceeded: Avg power
>>> 43370, limit 1023
>>> [   53.576740] intel ips 0000:00:1f.6: MCP limit exceeded: Avg power
>>> 64728, limit 1023
>>>
>>> This is an idle machine which starts printing these messages about 30
>>> seconds after boot. Any thoughts?
>>
>> Actually, it looks like you have some non-upstream patches to the IPS
>> driver, maybe one of Joe's patches to add more debug output when limits
>> are exceeded?
>>

Its just a debug hack which I wrote (that I mentioned in the first 
email) so I could figure out why the driver was complaining.

>> At any rate, I think we're setting the MCP power limit incorrectly.
>> The BIOS must be giving us a limit in 0.1W units (though even then it
>> looks bogus); we need to clamp it to one of the available defaults.
>>
>> Joe has some code for that as well, I've just asked him to update his
>> patch, which we should get into 2.6.35.x.
>
> Just posted some fixes for this to the x86 driver list, in particular
> the "[PATCH 2/2] IPS driver: verify BIOS provided limits" should help a
> bit here, but I still have a bug to fix in the i915 driver to really
> make things work.
>

I'll be back from Asia by Monday and will give these patches a try.

rtg
-- 
Tim Gardner tim.gardner@canonical.com

  reply	other threads:[~2010-09-23 22:47 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-09-15 17:47 MCP limit log messages, 2.6.36-rc4 Tim Gardner
2010-09-15 19:20 ` Tim Gardner
2010-09-16 12:49   ` Jesse Barnes
2010-09-23 20:48 ` Jesse Barnes
2010-09-23 21:54   ` Jesse Barnes
2010-09-23 22:46     ` Tim Gardner [this message]
2010-09-24 16:18       ` Jesse Barnes
2010-09-28 16:34         ` Tim Gardner
2010-09-28 17:18           ` Jesse Barnes

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