On Mon, 22 Jun 2015, Peter Antoine <peter.antoine@xxxxxxxxx> 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. > > [backport of 4.1 commit 364aece01a2dd748fc36a1e8bf52ef639b0857bd] > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=89600 > Cc: stable@xxxxxxxxxxxxxxx # 4.0+ > Signed-off-by: Peter Antoine <peter.antoine@xxxxxxxxx> > Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx> > [Jani: fixed typo in subject, massaged the comments a bit] > Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx> Acked-by: Jani Nikula <jani.nikula@xxxxxxxxx> ...although based on the patch context I'm not sure why this needs a separate backport. Does it not cherry-pick cleanly to 4.0? The stable team should take care of these automatically. BR, Jani. > --- > drivers/gpu/drm/i915/i915_drv.c | 13 ++++++++++--- > 1 file changed, 10 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c > index ec4d932..169123a 100644 > --- a/drivers/gpu/drm/i915/i915_drv.c > +++ b/drivers/gpu/drm/i915/i915_drv.c > @@ -693,6 +693,16 @@ static int i915_drm_resume(struct drm_device *dev) > intel_init_pch_refclk(dev); > drm_mode_config_reset(dev); > > + /* > + * Interrupts have to be enabled before any batches are run. > + * If not the GPU will hang. i915_gem_init_hw() will initiate > + * batches to update/restore the context. > + * > + * Modeset enabling in intel_modeset_init_hw() also needs > + * working interrupts. > + */ > + 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"); > @@ -700,9 +710,6 @@ 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); > - > intel_modeset_init_hw(dev); > > spin_lock_irq(&dev_priv->irq_lock); > -- > 1.9.1 > -- Jani Nikula, Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe stable" in