drm/i915/ttm: consider CCS for backup objects

It seems we can have one or more framebuffers that are still pinned when
suspending lmem, in such a case we end up creating a shmem backup
object, instead of evicting the object directly, but this will skip
copying the CCS aux state, since we don't allocate the extra storage for
the CCS pages as part of the ttm_tt construction. Since we can already
deal with pinned objects just fine, it doesn't seem too nasty to just
extend to support dealing with the CCS aux state, if the object is a
pinned framebuffer. This fixes display corruption (like in gnome-shell)
seen on DG2 when returning from suspend.

Fixes: da0595ae ("drm/i915/migrate: Evict and restore the flatccs capable lmem obj")
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Nirmoy Das <nirmoy.das@intel.com>
Cc: Andrzej Hajda <andrzej.hajda@intel.com>
Cc: Shuicheng Lin <shuicheng.lin@intel.com>
Cc: <stable@vger.kernel.org> # v5.19+
Tested-by: Nirmoy Das <nirmoy.das@intel.com>
Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221212171958.82593-2-matthew.auld@intel.com

drivers/gpu/drm/i915/gem/i915_gem_object.c

@@ -785,6 +785,9 @@ bool i915_gem_object_needs_ccs_pages(struct drm_i915_gem_object *obj)
 	if (!HAS_FLAT_CCS(to_i915(obj->base.dev)))
 		return false;
 
+	if (obj->flags & I915_BO_ALLOC_CCS_AUX)
+		return true;
+
 	for (i = 0; i < obj->mm.n_placements; i++) {
 		/* Compression is not allowed for the objects with smem placement */
 		if (obj->mm.placements[i]->type == INTEL_MEMORY_SYSTEM)

drivers/gpu/drm/i915/gem/i915_gem_object_types.h

@@ -327,16 +327,18 @@ struct drm_i915_gem_object {
  * dealing with userspace objects the CPU fault handler is free to ignore this.
  */
 #define I915_BO_ALLOC_GPU_ONLY	  BIT(6)
+#define I915_BO_ALLOC_CCS_AUX	  BIT(7)
 #define I915_BO_ALLOC_FLAGS (I915_BO_ALLOC_CONTIGUOUS | \
 			     I915_BO_ALLOC_VOLATILE | \
 			     I915_BO_ALLOC_CPU_CLEAR | \
 			     I915_BO_ALLOC_USER | \
 			     I915_BO_ALLOC_PM_VOLATILE | \
 			     I915_BO_ALLOC_PM_EARLY | \
-			     I915_BO_ALLOC_GPU_ONLY)
-#define I915_BO_READONLY          BIT(7)
-#define I915_TILING_QUIRK_BIT     8 /* unknown swizzling; do not release! */
-#define I915_BO_PROTECTED         BIT(9)
+			     I915_BO_ALLOC_GPU_ONLY | \
+			     I915_BO_ALLOC_CCS_AUX)
+#define I915_BO_READONLY          BIT(8)
+#define I915_TILING_QUIRK_BIT     9 /* unknown swizzling; do not release! */
+#define I915_BO_PROTECTED         BIT(10)
 	/**
 	 * @mem_flags - Mutable placement-related flags
 	 *

drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c

@@ -50,6 +50,7 @@ static int i915_ttm_backup(struct i915_gem_apply_to_region *apply,
 		container_of(bo->bdev, typeof(*i915), bdev);
 	struct drm_i915_gem_object *backup;
 	struct ttm_operation_ctx ctx = {};
+	unsigned int flags;
 	int err = 0;
 
 	if (bo->resource->mem_type == I915_PL_SYSTEM || obj->ttm.backup)
@@ -65,7 +66,22 @@ static int i915_ttm_backup(struct i915_gem_apply_to_region *apply,
 	if (obj->flags & I915_BO_ALLOC_PM_VOLATILE)
 		return 0;
 
-	backup = i915_gem_object_create_shmem(i915, obj->base.size);
+	/*
+	 * It seems that we might have some framebuffers still pinned at this
+	 * stage, but for such objects we might also need to deal with the CCS
+	 * aux state. Make sure we force the save/restore of the CCS state,
+	 * otherwise we might observe display corruption, when returning from
+	 * suspend.
+	 */
+	flags = 0;
+	if (i915_gem_object_needs_ccs_pages(obj)) {
+		WARN_ON_ONCE(!i915_gem_object_is_framebuffer(obj));
+		WARN_ON_ONCE(!pm_apply->allow_gpu);
+
+		flags = I915_BO_ALLOC_CCS_AUX;
+	}
+	backup = i915_gem_object_create_region(i915->mm.regions[INTEL_REGION_SMEM],
+					       obj->base.size, 0, flags);
 	if (IS_ERR(backup))
 		return PTR_ERR(backup);