aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorSimon Ser <contact@emersion.fr>2021-07-08 12:11:10 +0200
committerSimon Ser <contact@emersion.fr>2021-07-08 17:06:20 +0200
commitd71ed635b90a12c1f1d096817aec9d00b2ad6a3d (patch)
tree3d6bc4aee560e60efbde589b5e413e7e84c4a5c6
parente035f2b9c42b39e3eff37d0fe98bfa6422877d7a (diff)
backend/drm: force linear layout for multi-GPU buffers
Some buffers need to be copied across GPUs. Such buffers need to be allocated with a format and modifier suitable for both the source and the destination. When explicit modifiers aren't supported, we were forcing the buffers to be allocated with a linear layout, because implicit modifiers aren't portable across GPUs. All is well with this case. When explicit modifiers are supported, we were advertising the whole list of destination modifiers, in the hope that the source might have some in common and might be able to allocate a buffer with a more optimized layout. This works well if the source supports explicit modifiers. However, if the source doesn't, then wlr_drm_format_intersect will fallback to implicit modifiers, and everything goes boom: the source uses a GPU-specific tiling and the destination interprets it as linear. To avoid this, just force linear unconditionally. We'll be able to revert this once we have a good way to indicate that an implicit modifier isn't supported in wlr_drm_format_set, see [1]. [1]: https://github.com/swaywm/wlroots/pull/2815 Closes: https://github.com/swaywm/wlroots/issues/3030
-rw-r--r--backend/drm/backend.c20
1 files changed, 7 insertions, 13 deletions
diff --git a/backend/drm/backend.c b/backend/drm/backend.c
index 1b840a9e..a1c7ce9c 100644
--- a/backend/drm/backend.c
+++ b/backend/drm/backend.c
@@ -248,21 +248,15 @@ struct wlr_backend *wlr_drm_backend_create(struct wl_display *display,
goto error_event;
}
+ // Force a linear layout. In case explicit modifiers aren't supported,
+ // the meaning of implicit modifiers changes from one GPU to the other.
+ // In case explicit modifiers are supported, we still have no guarantee
+ // that the buffer producer will support these, so they might fallback
+ // to implicit modifiers.
for (size_t i = 0; i < texture_formats->len; i++) {
const struct wlr_drm_format *fmt = texture_formats->formats[i];
- if (fmt->len == 0) {
- // Modifiers aren't supported. The implicit modifier changes
- // from a GPU to the other, so we can only accept linear
- // buffers
- wlr_drm_format_set_add(&drm->mgpu_formats, fmt->format,
- DRM_FORMAT_MOD_LINEAR);
- continue;
- }
-
- for (size_t j = 0; j < fmt->len; j++) {
- wlr_drm_format_set_add(&drm->mgpu_formats, fmt->format,
- fmt->modifiers[j]);
- }
+ wlr_drm_format_set_add(&drm->mgpu_formats, fmt->format,
+ DRM_FORMAT_MOD_LINEAR);
}
}