Re: [PATCH 7/7] Revert "drm/i915: Enable semaphores on BDW"

[Daniel Vetter <daniel@ffwll.ch>]

On Thu, Aug 07, 2014 at 01:05:52PM -0700, Rodrigo Vivi wrote:
> The rest of the series was a reference for the records of what I had and
> let semaphores on bdw a bit more stable. But even with them we still get
> hungs so please consider only to get the revert for now.

Thanks for the reminder, picked up for -fixes, thanks for the patch.
-Daniel
> 
> 
> On Mon, Aug 4, 2014 at 11:15 AM, Rodrigo Vivi <rodrigo.vivi@intel.com>
> wrote:
> 
> > This reverts commit 521e62e49a42661a4ee0102644517dbe2f100a23.
> >
> > Although POST_SYNC brought a bit of stability to Semaphores on BDW
> > it didn't solved all issues and some hungs can still occour when
> > semaphores are enabled on BDW. Also some sloweness can be found on some
> > igt tests, althoguth it apparently doesn't affect real workloads.
> >
> > Besides that, no real performance gain was found on our tests with
> > different
> > and even multiple workloads.
> >
> > Let's disable it again for now. At least until we are sure it is safe
> > to re-enable it.
> >
> > Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_drv.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_drv.c
> > b/drivers/gpu/drm/i915/i915_drv.c
> > index 6c4b25c..ec96f9a 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.c
> > +++ b/drivers/gpu/drm/i915/i915_drv.c
> > @@ -481,6 +481,10 @@ bool i915_semaphore_is_enabled(struct drm_device *dev)
> >         if (i915.semaphores >= 0)
> >                 return i915.semaphores;
> >
> > +       /* Until we get further testing... */
> > +       if (IS_GEN8(dev))
> > +               return false;
> > +
> >  #ifdef CONFIG_INTEL_IOMMU
> >         /* Enable semaphores on SNB when IO remapping is off */
> >         if (INTEL_INFO(dev)->gen == 6 && intel_iommu_gfx_mapped)
> > --
> > 1.9.3
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> >
> 
> 
> 
> -- 
> Rodrigo Vivi
> Blog: http://blog.vivi.eng.br

> _______________________________________________
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> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx


-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch