drm/i915: Clear wedged status upon resume

When we wake up from suspend, the device has been powered down and
should come back afresh. We should be able to safely remove the wedged
status from the previous session and start afresh.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170826110935.10237-2-chris@chris-wilson.co.uk
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>

drivers/gpu/drm/i915/i915_gem.c

@@ -4523,6 +4523,12 @@ static void assert_kernel_context_is_current(struct drm_i915_private *dev_priv)
 
 void i915_gem_sanitize(struct drm_i915_private *i915)
 {
+	if (i915_terminally_wedged(&i915->gpu_error)) {
+		mutex_lock(&i915->drm.struct_mutex);
+		i915_gem_unset_wedged(i915);
+		mutex_unlock(&i915->drm.struct_mutex);
+	}
+
 	/*
 	 * If we inherit context state from the BIOS or earlier occupants
 	 * of the GPU, the GPU may be in an inconsistent state when we