On 09/01/15 11:09, Daniel, Thomas wrote: > A previous commit enabled execlists by default: > > commit 27401d126b5b ("drm/i915/bdw: Enable execlists by default where > supported") > > This allowed routine testing of execlists which exposed a regression when > resuming from suspend. The cause was tracked down the to recent changes to > the > ring init sequence: > > commit 35a57ffbb108 ("drm/i915: Only init engines once") > > During a suspend/resume cycle the hardware Context Status Buffer write pointer > is reset. However since the recent changes to the init sequence the software > CSB > read pointer is no longer reset. This means that context status events are > not > handled correctly and new contexts are not written to the ELSP, resulting in > an > apparent GPU hang. > > Pending further changes to the ring init code, just move the > ring->next_context_status_buffer initialization into gen8_init_common_ring to > fix this regression. > > v2: Moved init into gen8_init_common_ring rather than context_enable after > feedback from Daniel Vetter. Updated commit msg to reflect this and also cite > commits related to the regression. Fixed bz link to correct bug. > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=88096 > Cc: Paulo Zanoni <paulo.r.zan...@intel.com> > Cc: Daniel Vetter <daniel.vet...@ffwll.ch> > Cc: Dave Gordon <david.s.gor...@intel.com> > Signed-off-by: Thomas Daniel <thomas.dan...@intel.com> > --- > drivers/gpu/drm/i915/intel_lrc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/intel_lrc.c > b/drivers/gpu/drm/i915/intel_lrc.c > index 7670a0f..e405b61 100644 > --- a/drivers/gpu/drm/i915/intel_lrc.c > +++ b/drivers/gpu/drm/i915/intel_lrc.c > @@ -1137,6 +1137,7 @@ static int gen8_init_common_ring(struct intel_engine_cs > *ring) > _MASKED_BIT_DISABLE(GFX_REPLAY_MODE) | > _MASKED_BIT_ENABLE(GFX_RUN_LIST_ENABLE)); > POSTING_READ(RING_MODE_GEN7(ring)); > + ring->next_context_status_buffer = 0; > DRM_DEBUG_DRIVER("Execlists enabled for %s\n", ring->name); > > memset(&ring->hangcheck, 0, sizeof(ring->hangcheck)); > @@ -1394,7 +1395,6 @@ static int logical_ring_init(struct drm_device *dev, > struct intel_engine_cs *rin > INIT_LIST_HEAD(&ring->execlist_queue); > INIT_LIST_HEAD(&ring->execlist_retired_req_list); > spin_lock_init(&ring->execlist_lock); > - ring->next_context_status_buffer = 0; > > ret = i915_cmd_parser_init_ring(ring); > if (ret) >
LGTM. Reviewed-by: Dave Gordon <david.s.gor...@intel.com> _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/intel-gfx