drm/amd/display: Drop dm_determine_update_type_for_commit

[Why]
This was added in the past to solve the issue of not knowing when
to stall for medium and full updates in DM.

Since DC is ultimately decides what requires bandwidth changes we
wanted to make use of it directly to determine this.

The problem is that we can't actually pass any of the stream or surface
updates into DC global validation, so we don't actually check if the new
configuration is valid - we just validate the old existing config
instead and stall for outstanding commits to finish.

There's also the problem of grabbing the DRM private object for
pageflips which can lead to page faults in the case where commits
execute out of order and free a DRM private object state that was
still required for commit tail.

[How]
Now that we reset the plane in DM with the same conditions DC checks
we can have planes go through DC validation and we know when we need
to check and stall based on whether the stream or planes changed.

We mark lock_and_validation_needed whenever we've done this, so just
go back to using that instead of dm_determine_update_type_for_commit.

Since we'll skip resetting the plane for a pageflip we will no longer
grab the DRM private object for pageflips as well, avoiding the
page fault issued caused by pageflipping under load with commits
executing out of order.
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -8466,161 +8466,6 @@ static int dm_update_plane_state(struct dc *dc,
 	return ret;
 }
 
-static int
-dm_determine_update_type_for_commit(struct amdgpu_display_manager *dm,
-				    struct drm_atomic_state *state,
-				    enum surface_update_type *out_type)
-{
-	struct dc *dc = dm->dc;
-	struct dm_atomic_state *dm_state = NULL, *old_dm_state = NULL;
-	int i, j, num_plane, ret = 0;
-	struct drm_plane_state *old_plane_state, *new_plane_state;
-	struct dm_plane_state *new_dm_plane_state, *old_dm_plane_state;
-	struct drm_crtc *new_plane_crtc;
-	struct drm_plane *plane;
-
-	struct drm_crtc *crtc;
-	struct drm_crtc_state *new_crtc_state, *old_crtc_state;
-	struct dm_crtc_state *new_dm_crtc_state, *old_dm_crtc_state;
-	struct dc_stream_status *status = NULL;
-	enum surface_update_type update_type = UPDATE_TYPE_FAST;
-	struct surface_info_bundle {
-		struct dc_surface_update surface_updates[MAX_SURFACES];
-		struct dc_plane_info plane_infos[MAX_SURFACES];
-		struct dc_scaling_info scaling_infos[MAX_SURFACES];
-		struct dc_flip_addrs flip_addrs[MAX_SURFACES];
-		struct dc_stream_update stream_update;
-	} *bundle;
-
-	bundle = kzalloc(sizeof(*bundle), GFP_KERNEL);
-
-	if (!bundle) {
-		DRM_ERROR("Failed to allocate update bundle\n");
-		/* Set type to FULL to avoid crashing in DC*/
-		update_type = UPDATE_TYPE_FULL;
-		goto cleanup;
-	}
-
-	for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) {
-
-		memset(bundle, 0, sizeof(struct surface_info_bundle));
-
-		new_dm_crtc_state = to_dm_crtc_state(new_crtc_state);
-		old_dm_crtc_state = to_dm_crtc_state(old_crtc_state);
-		num_plane = 0;
-
-		if (new_dm_crtc_state->stream != old_dm_crtc_state->stream) {
-			update_type = UPDATE_TYPE_FULL;
-			goto cleanup;
-		}
-
-		if (!new_dm_crtc_state->stream)
-			continue;
-
-		for_each_oldnew_plane_in_state(state, plane, old_plane_state, new_plane_state, j) {
-			struct dc_plane_info *plane_info = &bundle->plane_infos[num_plane];
-			struct dc_flip_addrs *flip_addr = &bundle->flip_addrs[num_plane];
-			struct dc_scaling_info *scaling_info = &bundle->scaling_infos[num_plane];
-
-			new_plane_crtc = new_plane_state->crtc;
-			new_dm_plane_state = to_dm_plane_state(new_plane_state);
-			old_dm_plane_state = to_dm_plane_state(old_plane_state);
-
-			if (plane->type == DRM_PLANE_TYPE_CURSOR)
-				continue;
-
-			if (new_dm_plane_state->dc_state != old_dm_plane_state->dc_state) {
-				update_type = UPDATE_TYPE_FULL;
-				goto cleanup;
-			}
-
-			if (crtc != new_plane_crtc)
-				continue;
-
-			bundle->surface_updates[num_plane].surface =
-					new_dm_plane_state->dc_state;
-
-			if (new_crtc_state->mode_changed) {
-				bundle->stream_update.dst = new_dm_crtc_state->stream->dst;
-				bundle->stream_update.src = new_dm_crtc_state->stream->src;
-			}
-
-			if (new_crtc_state->color_mgmt_changed) {
-				bundle->surface_updates[num_plane].gamma =
-						new_dm_plane_state->dc_state->gamma_correction;
-				bundle->surface_updates[num_plane].in_transfer_func =
-						new_dm_plane_state->dc_state->in_transfer_func;
-				bundle->surface_updates[num_plane].gamut_remap_matrix =
-						&new_dm_plane_state->dc_state->gamut_remap_matrix;
-				bundle->stream_update.gamut_remap =
-						&new_dm_crtc_state->stream->gamut_remap_matrix;
-				bundle->stream_update.output_csc_transform =
-						&new_dm_crtc_state->stream->csc_color_matrix;
-				bundle->stream_update.out_transfer_func =
-						new_dm_crtc_state->stream->out_transfer_func;
-			}
-
-			ret = fill_dc_scaling_info(new_plane_state,
-						   scaling_info);
-			if (ret)
-				goto cleanup;
-
-			bundle->surface_updates[num_plane].scaling_info = scaling_info;
-
-			if (new_plane_state->fb) {
-				ret = fill_dc_plane_info_and_addr(
-					dm->adev, new_plane_state,
-					new_dm_plane_state->tiling_flags,
-					plane_info, &flip_addr->address,
-					new_dm_plane_state->tmz_surface, false);
-				if (ret)
-					goto cleanup;
-
-				bundle->surface_updates[num_plane].plane_info = plane_info;
-				bundle->surface_updates[num_plane].flip_addr = flip_addr;
-			}
-
-			num_plane++;
-		}
-
-		if (num_plane == 0)
-			continue;
-
-		ret = dm_atomic_get_state(state, &dm_state);
-		if (ret)
-			goto cleanup;
-
-		old_dm_state = dm_atomic_get_old_state(state);
-		if (!old_dm_state) {
-			ret = -EINVAL;
-			goto cleanup;
-		}
-
-		status = dc_stream_get_status_from_state(old_dm_state->context,
-							 new_dm_crtc_state->stream);
-		bundle->stream_update.stream = new_dm_crtc_state->stream;
-		/*
-		 * TODO: DC modifies the surface during this call so we need
-		 * to lock here - find a way to do this without locking.
-		 */
-		mutex_lock(&dm->dc_lock);
-		update_type = dc_check_update_surfaces_for_stream(
-				dc,	bundle->surface_updates, num_plane,
-				&bundle->stream_update, status);
-		mutex_unlock(&dm->dc_lock);
-
-		if (update_type > UPDATE_TYPE_MED) {
-			update_type = UPDATE_TYPE_FULL;
-			goto cleanup;
-		}
-	}
-
-cleanup:
-	kfree(bundle);
-
-	*out_type = update_type;
-	return ret;
-}
 #if defined(CONFIG_DRM_AMD_DC_DCN)
 static int add_affected_mst_dsc_crtcs(struct drm_atomic_state *state, struct drm_crtc *crtc)
 {
@@ -8661,8 +8506,7 @@ static int add_affected_mst_dsc_crtcs(struct drm_atomic_state *state, struct drm
  * acquired. For full updates case which removes/adds/updates streams on one
  * CRTC while flipping on another CRTC, acquiring global lock will guarantee
  * that any such full update commit will wait for completion of any outstanding
- * flip using DRMs synchronization events. See
- * dm_determine_update_type_for_commit()
+ * flip using DRMs synchronization events.
  *
  * Note that DM adds the affected connectors for all CRTCs in state, when that
  * might not seem necessary. This is because DC stream creation requires the
@@ -8683,15 +8527,8 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
 	struct drm_crtc_state *old_crtc_state, *new_crtc_state;
 	struct drm_plane *plane;
 	struct drm_plane_state *old_plane_state, *new_plane_state;
-	enum surface_update_type update_type = UPDATE_TYPE_FAST;
-	enum surface_update_type overall_update_type = UPDATE_TYPE_FAST;
 	enum dc_status status;
 	int ret, i;
-
-	/*
-	 * This bool will be set for true for any modeset/reset
-	 * or plane update which implies non fast surface update.
-	 */
 	bool lock_and_validation_needed = false;
 
 	ret = drm_atomic_helper_check_modeset(dev, state);
@@ -8885,27 +8722,23 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
 		if (!is_scaling_state_different(dm_new_con_state, dm_old_con_state))
 			continue;
 
-		overall_update_type = UPDATE_TYPE_FULL;
 		lock_and_validation_needed = true;
 	}
 
-	ret = dm_determine_update_type_for_commit(&adev->dm, state, &update_type);
-	if (ret)
-		goto fail;
-
-	if (overall_update_type < update_type)
-		overall_update_type = update_type;
-
-	/*
-	 * lock_and_validation_needed was an old way to determine if we need to set
-	 * the global lock. Leaving it in to check if we broke any corner cases
-	 * lock_and_validation_needed true = UPDATE_TYPE_FULL or UPDATE_TYPE_MED
-	 * lock_and_validation_needed false = UPDATE_TYPE_FAST
+	/**
+	 * Streams and planes are reset when there are changes that affect
+	 * bandwidth. Anything that affects bandwidth needs to go through
+	 * DC global validation to ensure that the configuration can be applied
+	 * to hardware.
+	 *
+	 * We have to currently stall out here in atomic_check for outstanding
+	 * commits to finish in this case because our IRQ handlers reference
+	 * DRM state directly - we can end up disabling interrupts too early
+	 * if we don't.
+	 *
+	 * TODO: Remove this stall and drop DM state private objects.
 	 */
-	if (lock_and_validation_needed && overall_update_type <= UPDATE_TYPE_FAST)
-		WARN(1, "Global lock should be Set, overall_update_type should be UPDATE_TYPE_MED or UPDATE_TYPE_FULL");
-
-	if (overall_update_type > UPDATE_TYPE_FAST) {
+	if (lock_and_validation_needed) {
 		ret = dm_atomic_get_state(state, &dm_state);
 		if (ret)
 			goto fail;
@@ -8987,7 +8820,9 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
 		struct dm_crtc_state *dm_new_crtc_state =
 			to_dm_crtc_state(new_crtc_state);
 
-		dm_new_crtc_state->update_type = (int)overall_update_type;
+		dm_new_crtc_state->update_type = lock_and_validation_needed ?
+							 UPDATE_TYPE_FULL :
+							 UPDATE_TYPE_FAST;
 	}
 
 	/* Must be success */