drm/i915/dpt: Use shmem for dpt objects

Dpt objects that are created from internal get evicted when there is
memory pressure and do not get restored when pinned during scanout. The
pinned page table entries look corrupted and programming the display
engine with the incorrect pte's result in DE throwing pipe faults.

Create DPT objects from shmem and mark the object as dirty when pinning so
that the object is restored when shrinker evicts an unpinned buffer object.

v2: Unconditionally mark the dpt objects dirty during pinning(Chris).

Fixes: 0dc987b ("drm/i915/display: Add smem fallback allocation for dpt")
Cc: <[email protected]> # v6.0+
Cc: Ville Syrjälä <[email protected]>
Cc: Tvrtko Ursulin <[email protected]>
Suggested-by: Chris Wilson <[email protected]>
Signed-off-by: Fei Yang <[email protected]>
Signed-off-by: Radhakrishna Sripada <[email protected]>
Reviewed-by: Tvrtko Ursulin <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
(cherry picked from commit e91a777)
Signed-off-by: Tvrtko Ursulin <[email protected]>

Author: Radhakrishna Sripada

drivers/gpu/drm/i915/display/intel_dpt.c

@@ -166,6 +166,8 @@ struct i915_vma *intel_dpt_pin(struct i915_address_space *vm)
 		i915_vma_get(vma);
 	}
 
+	dpt->obj->mm.dirty = true;
+
 	atomic_dec(&i915->gpu_error.pending_fb_pin);
 	intel_runtime_pm_put(&i915->runtime_pm, wakeref);
 
@@ -261,7 +263,7 @@ intel_dpt_create(struct intel_framebuffer *fb)
 		dpt_obj = i915_gem_object_create_stolen(i915, size);
 	if (IS_ERR(dpt_obj) && !HAS_LMEM(i915)) {
 		drm_dbg_kms(&i915->drm, "Allocating dpt from smem\n");
-		dpt_obj = i915_gem_object_create_internal(i915, size);
+		dpt_obj = i915_gem_object_create_shmem(i915, size);
 	}
 	if (IS_ERR(dpt_obj))
 		return ERR_CAST(dpt_obj);