From 8ff205a26697efbd8506eb2a74413b040e07602b Mon Sep 17 00:00:00 2001
From: Julian Orth <ju.orth@gmail.com>
Date: Sat, 14 Mar 2026 14:04:58 +0100
Subject: [PATCH] gbm: handle render nodes that cannot allocate buffers

---
 src/video/drm.rs | 16 +++++++++++-----
 src/video/gbm.rs | 32 ++++++++++++++++++++++----------
 2 files changed, 33 insertions(+), 15 deletions(-)

diff --git a/src/video/drm.rs b/src/video/drm.rs
index a4396d08..80db5b5e 100644
--- a/src/video/drm.rs
+++ b/src/video/drm.rs
@@ -168,11 +168,13 @@ fn reopen(fd: c::c_int, need_primary: bool) -> Result<Rc<OwnedFd>, DrmError> {
         return Ok(Rc::new(fd));
     }
     let path = 'path: {
-        if get_node_type_from_fd(fd).map_err(DrmError::GetDeviceType)? == NodeType::Render {
-            break 'path uapi::format_ustr!("/proc/self/fd/{}", fd);
-        }
-        if !need_primary && let Ok(path) = render_node_name(fd) {
-            break 'path path;
+        if !need_primary {
+            if get_node_type_from_fd(fd).map_err(DrmError::GetDeviceType)? == NodeType::Render {
+                break 'path uapi::format_ustr!("/proc/self/fd/{}", fd);
+            }
+            if let Ok(path) = render_node_name(fd) {
+                break 'path path;
+            }
         }
         device_node_name(fd)?
     };
@@ -212,6 +214,10 @@ impl Drm {
         self.fd.raw()
     }
 
+    pub fn dup_primary(&self) -> Result<Self, DrmError> {
+        Self::reopen(self.fd.raw(), true)
+    }
+
     pub fn dup_render(&self) -> Result<Self, DrmError> {
         Self::reopen(self.fd.raw(), false)
     }
diff --git a/src/video/gbm.rs b/src/video/gbm.rs
index 52ebb7ae..eb34ca71 100644
--- a/src/video/gbm.rs
+++ b/src/video/gbm.rs
@@ -7,8 +7,8 @@ use {
             BO_USE_RENDERING, BO_USE_SCANOUT, BO_USE_WRITE, BufferObject, BufferUsage,
             MappedBuffer,
         },
-        format::{Format, formats},
-        utils::oserror::OsError,
+        format::{Format, XRGB8888, formats},
+        utils::{errorfmt::ErrorFmt, oserror::OsError},
         video::{
             INVALID_MODIFIER, Modifier,
             dmabuf::{DmaBuf, DmaBufIds, DmaBufPlane, PlaneVec},
@@ -214,14 +214,26 @@ unsafe fn export_bo(dmabuf_ids: &DmaBufIds, bo: *mut Bo) -> Result<DmaBuf, GbmEr
 
 impl GbmDevice {
     pub fn new(drm: &Drm) -> Result<Self, GbmError> {
-        let drm = drm.dup_render()?;
-        let dev = unsafe { gbm_create_device(drm.raw()) };
-        if dev.is_null() {
-            Err(GbmError::CreateDevice)
-        } else {
-            let dev = Rc::new(DeviceHolder { dev });
-            Ok(Self { drm, dev })
-        }
+        let open = |drm: Drm| {
+            let dev = unsafe { gbm_create_device(drm.raw()) };
+            if dev.is_null() {
+                Err(GbmError::CreateDevice)
+            } else {
+                let dev = Rc::new(DeviceHolder { dev });
+                Ok(Self { drm, dev })
+            }
+        };
+        let dma_buf_ids = DmaBufIds::default();
+        let create_bo =
+            |gbm: &GbmDevice| gbm.create_bo(&dma_buf_ids, 1, 1, XRGB8888, &[INVALID_MODIFIER], 0);
+        let gbm = open(drm.dup_render()?)?;
+        match create_bo(&gbm) {
+            Ok(..) => return Ok(gbm),
+            Err(e) => log::warn!("Render node cannot allocate buffers: {}", ErrorFmt(e)),
+        };
+        let gbm = open(drm.dup_primary()?)?;
+        create_bo(&gbm)?;
+        Ok(gbm)
     }
 
     pub fn raw(&self) -> *mut Device {