drm/i915: Force the GPU reset upon wedging

When declaring the GPU wedged, we do need to hit the GPU with the reset
hammer so that its state matches our presumed state during cleanup. If
the reset fails, it fails, and we may be unhappy but wedged. However, if
we are testing our wedge/unwedged handling, the desync carries over into
the next test and promptly explodes.

References: https://bugs.freedesktop.org/show_bug.cgi?id=106702
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190208153708.20023-3-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_reset.c

@@ -532,9 +532,6 @@ typedef int (*reset_func)(struct drm_i915_private *,
 
 static reset_func intel_get_gpu_reset(struct drm_i915_private *i915)
 {
-	if (!i915_modparams.reset)
-		return NULL;
-
 	if (INTEL_GEN(i915) >= 8)
 		return gen8_reset_engines;
 	else if (INTEL_GEN(i915) >= 6)
@@ -599,6 +596,9 @@ bool intel_has_gpu_reset(struct drm_i915_private *i915)
 	if (USES_GUC(i915))
 		return false;
 
+	if (!i915_modparams.reset)
+		return NULL;
+
 	return intel_get_gpu_reset(i915);
 }
 
@@ -824,7 +824,7 @@ void i915_gem_set_wedged(struct drm_i915_private *i915)
 		reset_prepare_engine(engine);
 
 	/* Even if the GPU reset fails, it should still stop the engines */
-	if (INTEL_GEN(i915) >= 5)
+	if (!INTEL_INFO(i915)->gpu_reset_clobbers_display)
 		intel_gpu_reset(i915, ALL_ENGINES);
 
 	for_each_engine(engine, i915, id) {