From mboxrd@z Thu Jan  1 00:00:00 1970
From: Guenter Roeck <linux@roeck-us.net>
Subject: 'Timed out waiting for forcewake old ack to clear' and hangup on
 IvyBridge system
Date: Fri, 21 Jun 2013 23:58:08 -0700
Message-ID: <20130622065808.GA20980@roeck-us.net>
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To: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org
Cc: linux-kernel@vger.kernel.org, Mika Kuoppala <mika.kuoppala@intel.com>, Jesse Barnes <jbarnes@virtuousgeek.org>, Daniel Vetter <daniel.vetter@ffwll.ch>, David Airlie <airlied@linux.ie>
List-Id: dri-devel@lists.freedesktop.org

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 ?

Thanks,
Guenter