render/allocator/gbm: require GBM 21.1

Mesa 21.1 was released back in 2021. Let's require it so that we
can simplify our build and remove the workaround.

render/allocator/gbm.c

@@ -9,7 +9,6 @@
 #include <wlr/util/log.h>
 #include <xf86drm.h>
 
-#include "config.h"
 #include "render/allocator/gbm.h"
 #include "render/drm_format_set.h"
 
@@ -39,40 +38,12 @@ static bool export_gbm_bo(struct gbm_bo *bo,
 	attribs.modifier = gbm_bo_get_modifier(bo);
 
 	int i;
-	int32_t handle = -1;
 	for (i = 0; i < attribs.n_planes; ++i) {
-#if HAVE_GBM_BO_GET_FD_FOR_PLANE
-		(void)handle;
-
 		attribs.fd[i] = gbm_bo_get_fd_for_plane(bo, i);
 		if (attribs.fd[i] < 0) {
 			wlr_log(WLR_ERROR, "gbm_bo_get_fd_for_plane failed");
 			goto error_fd;
 		}
-#else
-		// GBM is lacking a function to get a FD for a given plane. Instead,
-		// check all planes have the same handle. We can't use
-		// drmPrimeHandleToFD because that messes up handle ref'counting in
-		// the user-space driver.
-		union gbm_bo_handle plane_handle = gbm_bo_get_handle_for_plane(bo, i);
-		if (plane_handle.s32 < 0) {
-			wlr_log(WLR_ERROR, "gbm_bo_get_handle_for_plane failed");
-			goto error_fd;
-		}
-		if (i == 0) {
-			handle = plane_handle.s32;
-		} else if (plane_handle.s32 != handle) {
-			wlr_log(WLR_ERROR, "Failed to export GBM BO: "
-				"all planes don't have the same GEM handle");
-			goto error_fd;
-		}
-
-		attribs.fd[i] = gbm_bo_get_fd(bo);
-		if (attribs.fd[i] < 0) {
-			wlr_log(WLR_ERROR, "gbm_bo_get_fd failed");
-			goto error_fd;
-		}
-#endif
 
 		attribs.offset[i] = gbm_bo_get_offset(bo, i);
 		attribs.stride[i] = gbm_bo_get_stride_for_plane(bo, i);

render/allocator/meson.build

@@ -13,15 +13,12 @@ wlr_files += files(
 
 gbm = disabler()
 if 'gbm' in allocators or 'auto' in allocators
-	gbm = dependency('gbm', version: '>=17.1.0', required: 'gbm' in allocators)
+	gbm = dependency('gbm', version: '>=21.1', required: 'gbm' in allocators)
 endif
 if gbm.found()
 	wlr_files += files('gbm.c')
 	wlr_deps += gbm
 	features += { 'gbm-allocator': true }
-
-	has = cc.has_function('gbm_bo_get_fd_for_plane', dependencies: [gbm])
-	internal_config.set10('HAVE_GBM_BO_GET_FD_FOR_PLANE', has)
 endif
 
 udmabuf = false