Commit b29d26fb authored by Matthew Auld's avatar Matthew Auld
Browse files

drm/i915/migrate: fix corner case in CCS aux copying 



In the case of lmem -> lmem transfers, which is currently only possible
with small-bar systems, we need to ensure we copy the CCS aux state
as-is, rather than nuke it. This should fix some nasty display
corruption sometimes seen on DG2 small-bar systems, when also using
DG2_RC_CCS_CC for the surface.

Fixes: e3afc690 ("drm/i915/display: consider DG2_RC_CCS_CC when migrating buffers")
Signed-off-by: default avatarMatthew 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>
Reviewed-by: default avatarNirmoy Das <nirmoy.das@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221212171958.82593-1-matthew.auld@intel.com
parent 89270d00

drivers/gpu/drm/i915/gt/intel_migrate.c

+29 −8
Original line number Diff line number Diff line
@@ -839,14 +839,35 @@ intel_context_migrate_copy(struct intel_context *ce, 
			if (err)

				goto out_rq;



			if (src_is_lmem) {

				/*

				 * If the src is already in lmem, then we must

				 * be doing an lmem -> lmem transfer, and so

				 * should be safe to directly copy the CCS

				 * state. In this case we have either

				 * initialised the CCS aux state when first

				 * clearing the pages (since it is already

				 * allocated in lmem), or the user has

				 * potentially populated it, in which case we

				 * need to copy the CCS state as-is.

				 */

				err = emit_copy_ccs(rq,

						    dst_offset, INDIRECT_ACCESS,

						    src_offset, INDIRECT_ACCESS,

						    len);

			} else {

				/*

			 * While we can't always restore/manage the CCS state,

			 * we still need to ensure we don't leak the CCS state

			 * from the previous user, so make sure we overwrite it

			 * with something.

				 * While we can't always restore/manage the CCS

				 * state, we still need to ensure we don't leak

				 * the CCS state from the previous user, so make

				 * sure we overwrite it with something.

				 */

			err = emit_copy_ccs(rq, dst_offset, INDIRECT_ACCESS,

					    dst_offset, DIRECT_ACCESS, len);

				err = emit_copy_ccs(rq,

						    dst_offset, INDIRECT_ACCESS,

						    dst_offset, DIRECT_ACCESS,

						    len);

			}



			if (err)

				goto out_rq;