The patch below does not apply to the 4.0-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 364aece01a2dd748fc36a1e8bf52ef639b0857bd Mon Sep 17 00:00:00 2001 From: Peter Antoine <peter.antoine@xxxxxxxxx> Date: Mon, 11 May 2015 08:50:45 +0100 Subject: [PATCH] drm/i915: Avoid GPU hang when coming out of s3 or s4 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. 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> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index c302ffb5a168..a19d2c71e205 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -699,6 +699,16 @@ 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"); @@ -706,9 +716,6 @@ 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); -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html