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: e3afc690188b ("drm/i915/display: consider DG2_RC_CCS_CC when migrating
buffers")
Signed-off-by: Matthew Auld <matthew.a...@intel.com>
Cc: Ville Syrjälä <ville.syrj...@linux.intel.com>
Cc: Nirmoy Das <nirmoy....@intel.com>
Cc: Andrzej Hajda <andrzej.ha...@intel.com>
Cc: Shuicheng Lin <shuicheng....@intel.com>
---
drivers/gpu/drm/i915/gt/intel_migrate.c | 37 +++++++++++++++++++------
1 file changed, 29 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_migrate.c
b/drivers/gpu/drm/i915/gt/intel_migrate.c
index e08a739b7091..3f638f198796 100644
--- a/drivers/gpu/drm/i915/gt/intel_migrate.c
+++ b/drivers/gpu/drm/i915/gt/intel_migrate.c
@@ -839,14 +839,35 @@ intel_context_migrate_copy(struct intel_context *ce,
if (err)
goto out_rq;
- /*
- * 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);
+ 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.
+ */
+ err = emit_copy_ccs(rq,
+ dst_offset, INDIRECT_ACCESS,
+ dst_offset, DIRECT_ACCESS,
+ len);
+ }
+
if (err)
goto out_rq;
--
2.38.1
