From dbe71918aa55cbff412e5d32e4561d0b4f62bbd3 Mon Sep 17 00:00:00 2001
From: stefan11111 <stefan11111@shitposting.expert>
Date: Wed, 17 Dec 2025 02:48:49 +0200
Subject: [PATCH] gbm: Implement dmabuf export for dumb buffers

Signed-off-by: stefan11111 <stefan11111@shitposting.expert>
---
 src/gbm/backends/dri/gbm_dri.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/gbm/backends/dri/gbm_dri.c b/src/gbm/backends/dri/gbm_dri.c
index 6640f16da77..fcb13d4532f 100644
--- a/src/gbm/backends/dri/gbm_dri.c
+++ b/src/gbm/backends/dri/gbm_dri.c
@@ -32,6 +32,7 @@
 #include <stdbool.h>
 #include <string.h>
 #include <errno.h>
+#include <fcntl.h> /* for O_RDWR, which DRM_RDWR is defined as */
 #include <limits.h>
 #include <assert.h>
 #include <sys/types.h>
@@ -446,8 +447,19 @@ gbm_dri_bo_get_fd(struct gbm_bo *_bo)
    struct gbm_dri_bo *bo = gbm_dri_bo(_bo);
    int fd;
 
-   if (bo->image == NULL)
+   if (bo->image == NULL) {
+#ifdef HAVE_LIBDRM
+      struct gbm_dri_device *dri = gbm_dri_device(_bo->gbm);
+      if (dri->has_dmabuf_export) {
+         int ret;
+         int prime_fd = -1;
+         ret = drmPrimeHandleToFD(dri->base.v0.fd, bo->handle, DRM_RDWR, &prime_fd);
+         if (!ret)
+            return prime_fd;
+      }
+#endif
       return -1;
+   }
 
    if (!dri2_query_image(bo->image, __DRI_IMAGE_ATTRIB_FD, &fd))
       return -1;