[Intel-gfx] [PATCH v3 2/2] drm/i915/display: Do not use stolen on MTL

[Nirmoy Das]

Use smem on MTL due to a HW bug in MTL that prevents
reading from stolen memory using LMEM BAR.

v2 and v3: improve stolen skip detection(Andrzej)

Cc: Oak Zeng <oak.zeng at intel.com>
Cc: Jani Nikula <jani.nikula at linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Cc: Andi Shyti <andi.shyti at linux.intel.com>
Cc: Andrzej Hajda <andrzej.hajda at intel.com>
Signed-off-by: Nirmoy Das <nirmoy.das at intel.com>
Reviewed-by: Oak Zeng <oak.zeng at intel.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda at intel.com>
Reviewed-by: Andi Shyti <andi.shyti at linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_fbdev.c   | 4 +++-
 drivers/gpu/drm/i915/display/intel_overlay.c | 5 +++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_fbdev.c b/drivers/gpu/drm/i915/display/intel_fbdev.c
index 1cc0ddc6a310..491b6e22edad 100644
--- a/drivers/gpu/drm/i915/display/intel_fbdev.c
+++ b/drivers/gpu/drm/i915/display/intel_fbdev.c
@@ -187,8 +187,10 @@ static int intelfb_alloc(struct drm_fb_helper *helper,
 		 * If the FB is too big, just don't use it since fbdev is not very
 		 * important and we should probably use that space with FBC or other
 		 * features.
+		 *
+		 * Also skip stolen on MTL as Wa_22018444074 mitigation.
 		 */
-		if (size * 2 < dev_priv->dsm.usable_size)
+		if (!(IS_METEORLAKE(dev_priv)) && size * 2 < dev_priv->dsm.usable_size)
 			obj = i915_gem_object_create_stolen(dev_priv, size);
 		if (IS_ERR(obj))
 			obj = i915_gem_object_create_shmem(dev_priv, size);
diff --git a/drivers/gpu/drm/i915/display/intel_overlay.c b/drivers/gpu/drm/i915/display/intel_overlay.c
index d6fe2bbabe55..09c1aa1427ad 100644
--- a/drivers/gpu/drm/i915/display/intel_overlay.c
+++ b/drivers/gpu/drm/i915/display/intel_overlay.c
@@ -1348,11 +1348,12 @@ int intel_overlay_attrs_ioctl(struct drm_device *dev, void *data,
 static int get_registers(struct intel_overlay *overlay, bool use_phys)
 {
 	struct drm_i915_private *i915 = overlay->i915;
-	struct drm_i915_gem_object *obj;
+	struct drm_i915_gem_object *obj = ERR_PTR(-ENODEV);
 	struct i915_vma *vma;
 	int err;
 
-	obj = i915_gem_object_create_stolen(i915, PAGE_SIZE);
+	if (!IS_METEORLAKE(i915)) /* Wa_22018444074 */
+		obj = i915_gem_object_create_stolen(i915, PAGE_SIZE);
 	if (IS_ERR(obj))
 		obj = i915_gem_object_create_internal(i915, PAGE_SIZE);
 	if (IS_ERR(obj))
-- 
2.39.0