FAILED: patch "[PATCH] drm/i915: Avoid GPU hang when coming out of s3 or s4" failed to apply to 4.0-stable tree

From 364aece01a2dd748fc36a1e8bf52ef639b0857bd Mon Sep 17 00:00:00 2001

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 <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 364aece01a2dd748fc36a1e8bf52ef639b0857bd Mon Sep 17 00:00:00 2001
From: Peter Antoine <[email protected]>
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 <[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.

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 +10 -3

index c302ffb5a168..a19d2c71e205 100644
@@ -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);