On Wed, Feb 13, 2013 at 04:23:27PM +0100, Daniel Vetter wrote:
> On Tue, Jan 29, 2013 at 06:13:34PM +0200, ville.syrj...@linux.intel.com wrote:
> > From: Ville Syrjälä <ville.syrj...@linux.intel.com>
> >
> > If a GPU reset occurs while a page flip has been submitted to the ring,
> > the flip will never complete once the ring has been reset.
> >
> > The GPU reset can be detected by sampling the reset_counter before the
> > flip is submitted, and then while waiting for the flip, the sampled
> > counter is compared with the current reset_counter value.
> >
> > Signed-off-by: Ville Syrjälä <ville.syrj...@linux.intel.com>
> > ---
> > drivers/gpu/drm/i915/intel_display.c | 14 +++++++++++++-
> > drivers/gpu/drm/i915/intel_drv.h | 3 +++
> > 2 files changed, 16 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_display.c
> > b/drivers/gpu/drm/i915/intel_display.c
> > index 4097118..e348a68 100644
> > --- a/drivers/gpu/drm/i915/intel_display.c
> > +++ b/drivers/gpu/drm/i915/intel_display.c
> > @@ -2862,10 +2862,12 @@ static bool intel_crtc_has_pending_flip(struct
> > drm_crtc *crtc)
> > {
> > struct drm_device *dev = crtc->dev;
> > struct drm_i915_private *dev_priv = dev->dev_private;
> > + struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
> > unsigned long flags;
> > bool pending;
> >
> > - if (i915_reset_in_progress(&dev_priv->gpu_error))
> > + if (i915_reset_in_progress(&dev_priv->gpu_error) ||
> > + intel_crtc->reset_counter !=
> > atomic_read(&dev_priv->gpu_error.reset_counter))
> > return false;
> >
> > spin_lock_irqsave(&dev->event_lock, flags);
> > @@ -6912,6 +6914,8 @@ static int intel_gen2_queue_flip(struct drm_device
> > *dev,
> > if (ret)
> > goto err_unpin;
> >
> > + intel_crtc->reset_counter =
> > atomic_read(&dev_priv->gpu_error.reset_counter);
>
> Ok no bikeshed about ->reset_counter, but a different one: Why does this
> need to be in the per-gen callback? Can't we just grab this before we call
> down into these callbacks? Imo races wrt the reset/hang code don't matter
> that much as long as we don't wait forever for a pageflip which won't
> happen. Hanging the gpu concurrently to pageflipping is undefined anyway
> right now ...
Yeah. It could be moved to happen a little earlier, and thus avoid the
duplication.
> -Daniel
>
> > +
> > /* Can't queue multiple flips, so wait for the previous
> > * one to finish before executing the next.
> > */
> > @@ -6956,6 +6960,8 @@ static int intel_gen3_queue_flip(struct drm_device
> > *dev,
> > if (ret)
> > goto err_unpin;
> >
> > + intel_crtc->reset_counter =
> > atomic_read(&dev_priv->gpu_error.reset_counter);
> > +
> > if (intel_crtc->plane)
> > flip_mask = MI_WAIT_FOR_PLANE_B_FLIP;
> > else
> > @@ -6997,6 +7003,8 @@ static int intel_gen4_queue_flip(struct drm_device
> > *dev,
> > if (ret)
> > goto err_unpin;
> >
> > + intel_crtc->reset_counter =
> > atomic_read(&dev_priv->gpu_error.reset_counter);
> > +
> > /* i965+ uses the linear or tiled offsets from the
> > * Display Registers (which do not change across a page-flip)
> > * so we need only reprogram the base address.
> > @@ -7045,6 +7053,8 @@ static int intel_gen6_queue_flip(struct drm_device
> > *dev,
> > if (ret)
> > goto err_unpin;
> >
> > + intel_crtc->reset_counter =
> > atomic_read(&dev_priv->gpu_error.reset_counter);
> > +
> > intel_ring_emit(ring, MI_DISPLAY_FLIP |
> > MI_DISPLAY_FLIP_PLANE(intel_crtc->plane));
> > intel_ring_emit(ring, fb->pitches[0] | obj->tiling_mode);
> > @@ -7111,6 +7121,8 @@ static int intel_gen7_queue_flip(struct drm_device
> > *dev,
> > if (ret)
> > goto err_unpin;
> >
> > + intel_crtc->reset_counter =
> > atomic_read(&dev_priv->gpu_error.reset_counter);
> > +
> > intel_ring_emit(ring, MI_DISPLAY_FLIP_I915 | plane_bit);
> > intel_ring_emit(ring, (fb->pitches[0] | obj->tiling_mode));
> > intel_ring_emit(ring, obj->gtt_offset + intel_crtc->dspaddr_offset);
> > diff --git a/drivers/gpu/drm/i915/intel_drv.h
> > b/drivers/gpu/drm/i915/intel_drv.h
> > index fcdfe42..a5521d9 100644
> > --- a/drivers/gpu/drm/i915/intel_drv.h
> > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > @@ -235,6 +235,9 @@ struct intel_crtc {
> > /* We can share PLLs across outputs if the timings match */
> > struct intel_pch_pll *pch_pll;
> > uint32_t ddi_pll_sel;
> > +
> > + /* reset counter value when the last flip was submitted */
> > + unsigned int reset_counter;
> > };
> >
> > struct intel_plane {
> > --
> > 1.7.12.4
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > 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
--
Ville Syrjälä
Intel OTC
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