drm/i915: Disable read only ppgtt support for gen11

On gen11 writing to read only ppgtt page causes a gpu hang. This behaviour is different than with previous gen where read only ppgtt access is supported. On those, the write is just dropped without visible side effects. Disable ro ppgtt support on gen11 until a solution can be found to bring it into line with its predecessors. References: HSDES#1807136187 References: https://bugzilla.freedesktop.org/show_bug.cgi?id=108569 Cc: Chris Wilson <[email protected]> Signed-off-by: Mika Kuoppala <[email protected]> Acked-by: Chris Wilson <[email protected]> Signed-off-by: Chris Wilson <[email protected]> Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
modi0012 · Apr 11, 2019 · 3936867 · 3936867
1 parent 0c441cb
commit 3936867
Showing 1 changed file with 8 additions and 3 deletions.
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -1228,7 +1228,7 @@ static int gen8_init_scratch(struct i915_address_space *vm)
 	vm->scratch_pte =
 		gen8_pte_encode(vm->scratch_page.daddr,
 				I915_CACHE_LLC,
-				PTE_READ_ONLY);
+				vm->has_read_only);
 
 	vm->scratch_pt = alloc_pt(vm);
 	if (IS_ERR(vm->scratch_pt)) {
@@ -1548,8 +1548,13 @@ static struct i915_hw_ppgtt *gen8_ppgtt_create(struct drm_i915_private *i915)
 
 	ppgtt_init(i915, ppgtt);
 
-	/* From bdw, there is support for read-only pages in the PPGTT. */
-	ppgtt->vm.has_read_only = true;
+	/*
+	 * From bdw, there is hw support for read-only pages in the PPGTT.
+	 *
+	 * Gen11 has HSDES#:1807136187 unresolved. Disable ro support
+	 * for now.
+	 */
+	ppgtt->vm.has_read_only = INTEL_GEN(i915) != 11;
 
 	/* There are only few exceptions for gen >=6. chv and bxt.
 	 * And we are not sure about the latter so play safe for now.