[Intel-gfx] [PATCH] drm/i915: A hotfix for making aliasing PPGTT work

[Zhi Wang]

This patch makes PPGTT page table non-shrinkable when using aliasing PPGTT
mode. It's just a temporary solution for making aliasing PPGTT mode work.

Cc: Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>
Cc: Michal Winiarski <michal.winiarski at intel.com>
Cc: Michel Thierry <michel.thierry at intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter at intel.com>
Cc: Zhenyu Wang <zhenyuw at linux.intel.com>
Cc: Zhiyuan Lv <zhiyuan.lv at intel.com>
Signed-off-by: Zhi Wang <zhi.a.wang at intel.com>
---
 drivers/gpu/drm/i915/i915_gem_gtt.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 22b3374..3af3b1c 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -754,10 +754,12 @@ static bool gen8_ppgtt_clear_pt(struct i915_address_space *vm,
 
 	GEM_BUG_ON(pte_end > GEN8_PTES);
 
-	bitmap_clear(pt->used_ptes, pte, num_entries);
+	if (USES_FULL_PPGTT(vm->i915)) {
+		bitmap_clear(pt->used_ptes, pte, num_entries);
 
-	if (bitmap_empty(pt->used_ptes, GEN8_PTES))
-		return true;
+		if (bitmap_empty(pt->used_ptes, GEN8_PTES))
+			return true;
+	}
 
 	pt_vaddr = kmap_px(pt);
 
-- 
1.9.1