[Intel-gfx] [PATCH] drm/i915: Disable WaGsvRC0ResidencyMethod for vlv

[Daniel Vetter]

On Thu, Mar 19, 2015 at 03:38:19PM +0200, David Weinehall wrote:
> On Thu, Mar 19, 2015 at 06:17:00PM +0530, Deepak S wrote:
> > 
> > 
> > On Thursday 19 March 2015 05:14 PM, David Weinehall wrote:
> > >On Thu, Mar 19, 2015 at 04:09:44PM +0530, deepak.s at linux.intel.com wrote:
> > >>From: Deepak S <deepak.s at linux.intel.com>
> > >>
> > >>Unfortunately WaGsvRC0ResidencyMethod causing system freeze on some
> > >>of the baytrail systems :(. Switching back to legacy mode rps.
> > >Is there any way to identify either what systems it's OK to use on,
> > >or to identif what Baytrail systems it isn't OK to use on?
> > >
> > >Just reverting this completely seems overly broad if it's possible to
> > >tell the difference between working and non-working systems.
> > 
> > Restricting the changes to few system will be the right way to go.
> > How do we get details of now working system?
> 
> That depends.  Who reported the non-working Baytrail-systems?
> And just as importantly, do we have Baytrail systems where this is
> confirmed to work?
> 
> If we can identify the respective revisions of the systems
> we might be able to discern the pattern and continue from there.

My experience with random crashes with rps on snb/ivb is that there's no
solid systems, just systems where no one has bothered to be really evil
yet.

I'd be really cautious with whitelisting since it tends to not really
solve the underlying bug (if there is one), usually blows up really fast
in size and is long-term unmaintainable. We've been there a few times with
other hacks and issues :(
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch