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

[Guenter Roeck <linux@roeck-us.net>]

On Wed, Jun 26, 2013 at 09:24:07AM -0700, Jesse Barnes wrote:
> On Sat, 22 Jun 2013 13:04:09 -0700
> Guenter Roeck <linux@roeck-us.net> wrote:
> 
> > On Sat, Jun 22, 2013 at 12:16:46PM -0700, Jesse Barnes wrote:
> > > On Fri, 21 Jun 2013 23:58:08 -0700
> > > Guenter Roeck <linux@roeck-us.net> 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...
> > > 
> > I installed the latest BIOS version (2.00b), but it did not fix the problem.
> > 
> > Is there some info (such as an Intel document describing what needs to be done)
> > which I could pass on to Supermicro ?
> > 
> > I think it would be helpful if the condition was detected and reported, if that
> > is possible. I spent two days so far tracking this down. It would be nice
> > if others would not have to go through the same experience.
> 
> I don't think there's anything public to share, but it's not a big deal
> to simply revert the patch in question.  That seems like the right
> thing to do anyway since we'd like stuff to work "out of the box" as
> much as possible.
> 
Agreed. Kind of unlikely that I can get Supermicro to listen to me anyway :(.

Who can initiate the revert ?

Thanks,
Guenter