render/allocator: use empty DRM lease to re-open node

This allows us to obtain a new DRM file description without relying
on filesystem permissions.
This commit is contained in:
Simon Ser 2021-09-02 10:52:43 +02:00
parent 4fae8f7be3
commit 1b65a80e9d

View File

@ -5,6 +5,7 @@
#include <unistd.h>
#include <wlr/util/log.h>
#include <xf86drm.h>
#include <xf86drmMode.h>
#include "backend/backend.h"
#include "render/allocator/allocator.h"
#include "render/allocator/drm_dumb.h"
@ -22,10 +23,22 @@ void wlr_allocator_init(struct wlr_allocator *alloc,
/* Re-open the DRM node to avoid GEM handle ref'counting issues. See:
* https://gitlab.freedesktop.org/mesa/drm/-/merge_requests/110
* TODO: don't assume we have the permission to just open the DRM node,
* find another way to re-open it.
*/
static int reopen_drm_node(int drm_fd, bool allow_render_node) {
if (drmIsMaster(drm_fd)) {
// Only recent kernels support empty leases
uint32_t lessee_id;
int lease_fd = drmModeCreateLease(drm_fd, NULL, 0, 0, &lessee_id);
if (lease_fd >= 0) {
return lease_fd;
} else if (lease_fd != -EINVAL && lease_fd != -EOPNOTSUPP) {
wlr_log_errno(WLR_ERROR, "drmModeCreateLease failed");
return -1;
}
wlr_log(WLR_DEBUG, "drmModeCreateLease failed, "
"falling back to plain open");
}
char *name = NULL;
if (allow_render_node) {
name = drmGetRenderDeviceNameFromFd(drm_fd);