On Mon, May 11, 2015 at 08:50:45AM +0100, Peter Antoine wrote: > This patch fixes a timing issue that causes a GPU hang when the system > comes out of power saving. > > During pm_resume, We are submitting batchbuffers before enabling > Interrupts this is causing us to miss the context switch interrupt, > and in consequence intel_execlists_handle_ctx_events is not triggered. > > This patch is based on a patch from Deepak S <deepak.s@xxxxxxxxx> > from another platform. > > The patch fixes an issue introduced by: > commit e7778be1eab918274f79603d7c17b3ec8be77386 > drm/i915: Fix startup failure in LRC mode after recent init changes > > The above patch added a call to init_context() to fix an issue introduced > by a previous patch. But, it then opened up a small timing window for the > batches being added by the init_context (basically setting up the context) > to complete before the interrupts have been turned on, thus hanging the > GPU. > > BUG: https://bugs.freedesktop.org/show_bug.cgi?id=89600 > Signed-off-by: Peter Antoine <peter.antoine@xxxxxxxxx> btw can you please follow up with a patch to encode these depencies? A WARN_ON(!irqs_enabled); in execlists_context_unqueue after the spinlock assert would be good I think. -Daniel > --- > drivers/gpu/drm/i915/i915_drv.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c > index 6bb6c47..90b1309 100644 > --- a/drivers/gpu/drm/i915/i915_drv.c > +++ b/drivers/gpu/drm/i915/i915_drv.c > @@ -734,6 +734,12 @@ static int i915_drm_resume(struct drm_device *dev) > intel_init_pch_refclk(dev); > drm_mode_config_reset(dev); > > + /* Interrupts have to enabled so that any batches that are completed > + * when the context is restarted are caught so that the ring buffer > + * does not handle. > + */ > + intel_runtime_pm_enable_interrupts(dev_priv); > + > mutex_lock(&dev->struct_mutex); > if (i915_gem_init_hw(dev)) { > DRM_ERROR("failed to re-initialize GPU, declaring wedged!\n"); > @@ -741,9 +747,7 @@ static int i915_drm_resume(struct drm_device *dev) > } > mutex_unlock(&dev->struct_mutex); > > - /* We need working interrupts for modeset enabling ... */ > - intel_runtime_pm_enable_interrupts(dev_priv); > - > + /* This must follow the pm enable interrupts */ > intel_modeset_init_hw(dev); > > spin_lock_irq(&dev_priv->irq_lock); > -- > 1.9.1 > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
