fdo-mirrors/mesa
1
0
Fork 0
mirror of https://gitlab.freedesktop.org/mesa/mesa.git synced 2026-05-07 00:38:48 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions 4

ir3: Align TCS per-patch output to 64 bytes to prevent stale reads

Browse source 
Empirically, TCS outputs have to be aligned to 64 bytes,
otherwise stale data may be read in rare cases. The exact
reason is not clear, but tests and proprietary driver behavior
strongly point at the need for 64 byte alignment.

Fixes tesselation issues in at least "Conan Exiles" but likely in many
more cases.

CC: mesa-stable

Signed-off-by: Danylo Piliaiev <dpiliaiev@igalia.com>
(cherry picked from commit 47251b2e2d)

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/40092>
This commit is contained in:
Danylo Piliaiev 2026-02-12 19:56:35 +01:00 • committed by Eric Engestrom
parent ba82a16761
commit ac49313d06
2 changed files with 8 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
.pick_status.json
View file

@ -594,7 +594,7 @@
"description": "ir3: Align TCS per-patch output to 64 bytes to prevent stale reads",
"nominated": true,
"nomination_type": 1,
"resolution": 0,
"resolution": 1,
"main_sha": null,
"because_sha": null,
"notes": null

8
src/freedreno/ir3/ir3_nir_lower_tess.c
View file

@ -665,7 +665,13 @@ ir3_nir_lower_tess_ctrl(nir_shader *shader, struct ir3_shader_variant *v,
build_primitive_map(shader, &state.map);
memcpy(v->output_loc, state.map.loc, sizeof(v->output_loc));
v->output_size = state.map.stride;
/* Empirically, TCS outputs have to be aligned to 64 bytes,
* otherwise stale data may be read in rare cases. The exact
* reason is not clear, but tests and proprietary driver behavior
* strongly point at the need for 64 byte alignment.
*/
v->output_size = ALIGN_POT(state.map.stride, 16);
nir_function_impl *impl = nir_shader_get_entrypoint(shader);
assert(impl);