From 5896a5c8c9c01b09af05b02cdb2ae275ef143959 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Fri, 13 Oct 2017 14:12:18 +0100
Subject: [PATCH] drm/i915: Always stop the rings before a missing GPU reset
Git-commit: 5896a5c8c9c01b09af05b02cdb2ae275ef143959
Patch-mainline: v4.15-rc1
References: FATE#322643 bsc#1055900

Always try to stop the rings, even if the GPU reset itself has been
disabled (via modparam i915.reset). This should at least stop the hw
from spinning in the background consuming resources (e.g. power and
memory bandwidth) letting the system rest-in-peace.

References: https://bugs.freedesktop.org/show_bug.cgi?id=103260
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171013131218.18013-2-chris@chris-wilson.co.uk
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/i915/intel_uncore.c |   13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -1403,6 +1403,9 @@ static void i915_stop_engines(struct drm
 	struct intel_engine_cs *engine;
 	enum intel_engine_id id;
 
+	if (INTEL_GEN(dev_priv) < 3)
+		return;
+
 	for_each_engine_masked(engine, dev_priv, engine_mask, id)
 		gen3_stop_engine(engine);
 }
@@ -1742,16 +1745,12 @@ static reset_func intel_get_gpu_reset(st
 
 int intel_gpu_reset(struct drm_i915_private *dev_priv, unsigned engine_mask)
 {
-	reset_func reset;
+	reset_func reset = intel_get_gpu_reset(dev_priv);
 	int retry;
 	int ret;
 
 	might_sleep();
 
-	reset = intel_get_gpu_reset(dev_priv);
-	if (reset == NULL)
-		return -ENODEV;
-
 	/* If the power well sleeps during the reset, the reset
 	 * request may be dropped and never completes (causing -EIO).
 	 */
@@ -1771,7 +1770,9 @@ int intel_gpu_reset(struct drm_i915_priv
 		 */
 		i915_stop_engines(dev_priv, engine_mask);
 
-		ret = reset(dev_priv, engine_mask);
+		ret = -ENODEV;
+		if (reset)
+			ret = reset(dev_priv, engine_mask);
 		if (ret != -ETIMEDOUT)
 			break;