On Wed, May 09, 2012 at 04:03:57PM -0700, Ben Widawsky wrote: > On Thu, 10 May 2012 00:40:20 +0200 > Daniel Vetter <daniel.vetter at ffwll.ch> wrote: > > > Inspired by the recent ppgtt regression report, where switching of > > dmar only for the gpu seems to fix things completely, I've looked > > again at the semaphores+vt-d situation. > > > > Contrary to my earlier testing a few months back my system is now > > stable with dmar disabled for the igd, and not only when disabling > > dmar completely. > > > > So I'm rather hopeful that all our recent fixes for snb have changed > > things for code and it's time to try enabling semaphores again. We've > > also had issues with enabling semaphores which are not vt-d related, > > but I guess these are all fixed by the autoreport-disabling and lazy > > request fix. And there's only one way to find out whether there are > > still other issues ... > > > > When I've tried to apply this patch I've noticed that semaphores on > > gen6 have already silently been added in > > > > commit 2911a35b2e4eb87ec48d03aeb11f019e51ae3c0d > > Author: Ben Widawsky <ben at bwidawsk.net> > > Date: Thu Apr 5 14:47:36 2012 -0700 > > > > drm/i915: use semaphores for the display plane > > > > Fix this up by only checking whether dmar is enabled on the gfx (not > > on the entire system). > > Heh. It wasn't on purpose! I want to blame this on git, but I honestly > don't know what happened. I guess because we've changed the defaults there so bloody often, this could easily be a bisect artifact ;-) > > Cc: Ben Widawsky <ben at bwidawsk.net> > > Cc: Chris Wilson <chris at chris-wilson.co.uk> > > Signed-Off-by: Daniel Vetter <daniel.vetter at ffwll.ch> > Reviewed-by: Ben Widawsky <ben at bwidawsk.net> Thanks, patch pushed out. -Daniel > > > --- > > drivers/gpu/drm/i915/i915_drv.c | 6 ++++-- > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c > > index 77b7a50..1ccfc23 100644 > > --- a/drivers/gpu/drm/i915/i915_drv.c > > +++ b/drivers/gpu/drm/i915/i915_drv.c > > @@ -407,9 +407,11 @@ bool i915_semaphore_is_enabled(struct drm_device *dev) > > if (i915_semaphores >= 0) > > return i915_semaphores; > > > > +#ifdef CONFIG_INTEL_IOMMU > > /* Enable semaphores on SNB when IO remapping is off */ > > - if (INTEL_INFO(dev)->gen == 6) > > - return !intel_iommu_enabled; > > + if (INTEL_INFO(dev)->gen == 6 && intel_iommu_gfx_mapped) > > + return false; > > +#endif > > > > return 1; > > } > > > > -- > Ben Widawsky, Intel Open Source Technology Center -- Daniel Vetter Mail: daniel at ffwll.ch Mobile: +41 (0)79 365 57 48
