[Intel-gfx] [PATCH] drm/i915/dpt: Use shmem for dpt objects

[Radhakrishna Sripada]

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.

Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Suggested-by: Chris Wilson <chris at chris-wilson.co.uk>
Signed-off-by: Fei Yang <fei.yang at intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada at intel.com>
---
 drivers/gpu/drm/i915/display/intel_dpt.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dpt.c b/drivers/gpu/drm/i915/display/intel_dpt.c
index 7c5fddb203ba..a57d18550a46 100644
--- a/drivers/gpu/drm/i915/display/intel_dpt.c
+++ b/drivers/gpu/drm/i915/display/intel_dpt.c
@@ -166,6 +166,9 @@ struct i915_vma *intel_dpt_pin(struct i915_address_space *vm)
 		i915_vma_get(vma);
 	}
 
+	if (i915_gem_object_is_shmem(dpt->obj))
+		dpt->obj->cache_dirty = true;
+
 	atomic_dec(&i915->gpu_error.pending_fb_pin);
 	intel_runtime_pm_put(&i915->runtime_pm, wakeref);
 
@@ -261,7 +264,7 @@ 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);
-- 
2.34.1