On Fri, Jun 03, 2016 at 05:08:47PM +0100, Chris Wilson wrote: > We have testcases to ensure that seqno wraparound works fine, so we can > forgo forcing everyone to encounter seqno wraparound during early > uptime. seqno wraparound incurs a full GPU stall so not forcing it > will eliminate one jitter from the early system. Using the testcases, we > have very deterministic testing which given how difficult it would be to > debug an issue (GPU hang) stemming from a wraparound using pure > postmortem analysis I see no value in forcing a wrap during boot. > > Advancing the global next_seqno after a GPU reset is equally pointless. > > References? https://bugs.freedesktop.org/show_bug.cgi?id=95023 > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Makes sense. Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx> > --- > drivers/gpu/drm/i915/i915_gem.c | 14 -------------- > 1 file changed, 14 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c > index bf5c93f2bd81..269d00a40483 100644 > --- a/drivers/gpu/drm/i915/i915_gem.c > +++ b/drivers/gpu/drm/i915/i915_gem.c > @@ -4858,12 +4858,6 @@ i915_gem_init_hw(struct drm_device *dev) > goto out; > } > > - /* > - * Increment the next seqno by 0x100 so we have a visible break > - * on re-initialisation > - */ > - ret = i915_gem_set_seqno(dev, dev_priv->next_seqno+0x100); > - > out: > intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL); > return ret; > @@ -5006,14 +5000,6 @@ i915_gem_load_init(struct drm_device *dev) > > dev_priv->relative_constants_mode = I915_EXEC_CONSTANTS_REL_GENERAL; > > - /* > - * Set initial sequence number for requests. > - * Using this number allows the wraparound to happen early, > - * catching any obvious problems. > - */ > - dev_priv->next_seqno = ((u32)~0 - 0x1100); > - dev_priv->last_seqno = ((u32)~0 - 0x1101); > - > INIT_LIST_HEAD(&dev_priv->mm.fence_list); > > init_waitqueue_head(&dev_priv->pending_flip_queue); > -- > 2.8.1 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
