From 04f7b24eccdfae680a36e9825fe0d61dcd5ed528 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Thu, 1 Jun 2017 10:04:46 +0100
Subject: [PATCH] drm/i915/guc: Assert that we switch between known ggtt->invalidate functions
Git-commit: 04f7b24eccdfae680a36e9825fe0d61dcd5ed528
Patch-mainline: v4.13-rc1
References: FATE#322643 bsc#1055900

When we enable the GuC, we enable an alternative mechanism for doing
post-GGTT update invalidation. Likewise, when we disable the GuC, we
restore the previous method. Assert that we change between known
endpoints, so that we can catch if we accidentally clobber some other
gen and if we change the invalidate routine without updating guc.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Oscar Mateo <oscar.mateo@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Arkadiusz Hiler <arkadiusz.hiler@intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170601090446.1334-1-chris@chris-wilson.co.uk
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/i915/i915_gem_gtt.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -3095,13 +3095,17 @@ int i915_ggtt_enable_hw(struct drm_i915_
 
 void i915_ggtt_enable_guc(struct drm_i915_private *i915)
 {
+	GEM_BUG_ON(i915->ggtt.invalidate != gen6_ggtt_invalidate);
+
 	i915->ggtt.invalidate = guc_ggtt_invalidate;
 }
 
 void i915_ggtt_disable_guc(struct drm_i915_private *i915)
 {
-	if (i915->ggtt.invalidate == guc_ggtt_invalidate)
-		i915->ggtt.invalidate = gen6_ggtt_invalidate;
+	/* We should only be called after i915_ggtt_enable_guc() */
+	GEM_BUG_ON(i915->ggtt.invalidate != guc_ggtt_invalidate);
+
+	i915->ggtt.invalidate = gen6_ggtt_invalidate;
 }
 
 void i915_gem_restore_gtt_mappings(struct drm_i915_private *dev_priv)