Re: 'Timed out waiting for forcewake old ack to clear' and hangupon IvyBridge system

[Jesse Barnes]

On Fri, 21 Jun 2013 23:58:08 -0700
Guenter Roeck <linux@xxxxxxxxxxxx> wrote:

> Hi all,
> 
> after upgrading one of my servers to 3.8, then 3.9.7 and 3.10-rc6, I started to
> see lots of "Timed out waiting for forcewake old ack to clear" error messages,
> including hang-ups especially if the system was highly loaded. With 3.5.24
> everything was fine.
> 
> After backing out commit 36ec8f877 (drm/i915: unconditionally use mt forcewake
> on hsw/ivb), everything is back to normal. The log message is still there, but
> only once during boot, and the system runs stable.
> 
> CPU is "Intel(R) Core(TM) i7-3770K CPU @ 3.50GHz", mainboard is Supermicro
> C7H61, BIOS version 2.00 dated 11/02/2012. Configuration file is whatever
> comes with Ubuntu; I'll be happy to provide a copy if anyone thinks it might
> help.
> 
> Any idea what else I can do besides using a special kernel with the backed out
> commit ? Is it possible that others have the same problem ?

Ouch, so a BIOS that uses the other forcewake mechanism seems to have
escaped.  Is there a newer one available for your system?  I'm hoping
it'll fix the issue, otherwise we may have to introduce both methods
for IVB again...

-- 
Jesse Barnes, Intel Open Source Technology Center
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