FAILED: patch "[PATCH] drm/i915: Fix system hang with EI UP masked on Haswell" failed to apply to 4.11-stable tree

The patch below does not apply to the 4.11-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: Mika Kuoppala <[email protected]>
Date: Thu, 13 Apr 2017 14:15:27 +0300
Subject: [PATCH] drm/i915: Fix system hang with EI UP masked on Haswell

Previously with commit a9c1f90c8e17
("drm/i915: Don't mask EI UP interrupt on IVB|SNB") certain, seemingly unrelated bit (GEN6_PM_RP_UP_EI_EXPIRED) was needed to be unmasked for IVB and SNB in order to prevent system hang with chained batchbuffers.

Our CI was seeing incomplete results with tests that used chained batches and it was found out that HSW needs to have this same bit unmasked to reliably survive chained batches.

Always unmask GEN6_PM_RP_UP_EI_EXPIRED on Haswell to prevent system hang with batch chaining.

Testcase: igt/gem_exec_fence/nb-await-default
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100672

index d9d196977f4a..fd97fe00cd0d 100644
@@ -4252,12 +4252,12 @@ void intel_irq_init(struct drm_i915_private *dev_priv)
 	dev_priv->rps.pm_intrmsk_mbz = 0;
 
 	/*
-	 * SNB,IVB can while VLV,CHV may hard hang on looping batchbuffer
+	 * SNB,IVB,HSW can while VLV,CHV may hard hang on looping batchbuffer
 	 * if GEN6_PM_UP_EI_EXPIRED is masked.
 	 *
 	 * TODO: verify if this can be reproduced on VLV,CHV.
 	 */
-	if (INTEL_INFO(dev_priv)->gen <= 7 && !IS_HASWELL(dev_priv))
+	if (INTEL_INFO(dev_priv)->gen <= 7)
 		dev_priv->rps.pm_intrmsk_mbz |= GEN6_PM_RP_UP_EI_EXPIRED;
 
 	if (INTEL_INFO(dev_priv)->gen >= 8)