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 <[email protected]> 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: [email protected] # 4.0+ Signed-off-by: Peter Antoine <[email protected]> Reviewed-by: Daniel Vetter <[email protected]> [Jani: fixed typo in subject, massaged the comments a bit] Signed-off-by: Jani Nikula <[email protected]> --- 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 -- To unsubscribe from this list: send the line "unsubscribe stable" in
