buffer: don't destroy DMA-BUF textures with wl_buffer

After some discussions on #wayland, it seems that as soon as you
hold a reference to a DMA-BUF (via EGLImage for instance), the
underlying memory won't get free'd. The client is allowed to
re-use the DMA-BUF and upload something else to it though.
This commit is contained in:
emersion 2018-06-14 10:15:14 +01:00
parent 73f924b5ec
commit da114d5013
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@ -43,11 +43,12 @@ static void buffer_resource_handle_destroy(struct wl_listener *listener,
wl_list_init(&buffer->resource_destroy.link); wl_list_init(&buffer->resource_destroy.link);
buffer->resource = NULL; buffer->resource = NULL;
if (!buffer->released) { // At this point, if the wl_buffer comes from linux-dmabuf or wl_drm, we
// The texture becomes invalid // still haven't released it (ie. we'll read it in the future) but the
wlr_texture_destroy(buffer->texture); // client destroyed it. Reading the texture itself should be fine because
buffer->texture = NULL; // we still hold a reference to the DMA-BUF via the texture. However the
} // client could decide to re-use the same DMA-BUF for something else, in
// which case we'll read garbage. We decide to accept this risk.
} }
struct wlr_buffer *wlr_buffer_create(struct wlr_renderer *renderer, struct wlr_buffer *wlr_buffer_create(struct wlr_renderer *renderer,
@ -80,6 +81,10 @@ struct wlr_buffer *wlr_buffer_create(struct wlr_renderer *renderer,
struct wlr_dmabuf_buffer *dmabuf = struct wlr_dmabuf_buffer *dmabuf =
wlr_dmabuf_buffer_from_buffer_resource(resource); wlr_dmabuf_buffer_from_buffer_resource(resource);
texture = wlr_texture_from_dmabuf(renderer, &dmabuf->attributes); texture = wlr_texture_from_dmabuf(renderer, &dmabuf->attributes);
// We have imported the DMA-BUF, but we need to prevent the client from
// re-using the same DMA-BUF for the next frames, so we don't release
// the buffer yet.
} else { } else {
wlr_log(L_ERROR, "Cannot upload texture: unknown buffer type"); wlr_log(L_ERROR, "Cannot upload texture: unknown buffer type");
return NULL; return NULL;