screencopy: Pass the node we're using to attach_buffer

Seems to make sure the compositor renders workspace with that GPU, so it
actually captures successfully.

src/wayland/buffer.rs

@@ -8,14 +8,23 @@ use cctk::{
     },
 };
 use cosmic::iced::widget::image;
-use std::os::fd::{AsFd, OwnedFd};
+use std::{
+    os::fd::{AsFd, OwnedFd},
+    path::{Path, PathBuf},
+};
 use wayland_protocols::wp::linux_dmabuf::zv1::client::zwp_linux_buffer_params_v1;
 
 use super::AppData;
 
 enum BufferBacking {
-    Shm { pool: RawPool },
-    Dmabuf { fd: OwnedFd, stride: u32 },
+    Shm {
+        pool: RawPool,
+    },
+    Dmabuf {
+        fd: OwnedFd,
+        node: PathBuf,
+        stride: u32,
+    },
 }
 
 pub struct Buffer {
@@ -53,7 +62,7 @@ impl AppData {
         needs_linear: bool,
     ) -> Option<(BufferBacking, wl_buffer::WlBuffer)> {
         // TODO Handle errors in some way
-        let gbm = self.gbm.as_ref()?;
+        let (node, gbm) = self.gbm.as_ref()?;
         let feedback = self.dmabuf_feedback.as_ref()?;
         let formats = feedback.format_table();
         let format_info = feedback
@@ -90,7 +99,14 @@ impl AppData {
             )
             .0;
 
-        Some((BufferBacking::Dmabuf { fd, stride }, buffer))
+        Some((
+            BufferBacking::Dmabuf {
+                fd,
+                node: node.clone(),
+                stride,
+            },
+            buffer,
+        ))
     }
 
     pub fn create_buffer(&self, buffer_infos: &[BufferInfo]) -> Buffer {
@@ -135,7 +151,11 @@ impl Buffer {
         let pixels = match &mut self.backing {
             BufferBacking::Shm { pool } => pool.mmap().to_vec(),
             // NOTE: Only will work with linear modifier
-            BufferBacking::Dmabuf { fd, stride } => {
+            BufferBacking::Dmabuf {
+                fd,
+                node: _,
+                stride,
+            } => {
                 // XXX Error handling?
                 let mmap = memmap2::Mmap::map(&*fd).unwrap();
                 if self.buffer_info.stride == self.buffer_info.width * 4 {
@@ -156,6 +176,13 @@ impl Buffer {
         };
         image::Handle::from_pixels(self.buffer_info.width, self.buffer_info.height, pixels)
     }
+
+    pub fn node(&self) -> Option<&Path> {
+        match &self.backing {
+            BufferBacking::Shm { .. } => None,
+            BufferBacking::Dmabuf { node, .. } => Some(node),
+        }
+    }
 }
 
 impl Drop for Buffer {

src/wayland/dmabuf.rs

@@ -6,7 +6,7 @@ use cctk::{
     wayland_client::{protocol::wl_buffer, Connection, QueueHandle},
 };
 
-use std::{fs, io, os::unix::fs::MetadataExt};
+use std::{fs, io, os::unix::fs::MetadataExt, path::PathBuf};
 
 use wayland_protocols::wp::linux_dmabuf::zv1::client::{
     zwp_linux_buffer_params_v1::ZwpLinuxBufferParamsV1,
@@ -65,13 +65,13 @@ impl DmabufHandler for AppData {
     }
 }
 
-fn find_gbm_device(dev: u64) -> io::Result<Option<gbm::Device<fs::File>>> {
+fn find_gbm_device(dev: u64) -> io::Result<Option<(PathBuf, gbm::Device<fs::File>)>> {
     for i in std::fs::read_dir("/dev/dri")? {
         let i = i?;
         if i.metadata()?.rdev() == dev {
             let file = fs::File::options().read(true).write(true).open(i.path())?;
             eprintln!("Opened gbm main device '{}'", i.path().display());
-            return Ok(Some(gbm::Device::new(file)?));
+            return Ok(Some((i.path(), gbm::Device::new(file)?)));
         }
     }
     Ok(None)

src/wayland/mod.rs

@@ -40,6 +40,7 @@ use std::{
     cell::RefCell,
     collections::{HashMap, HashSet},
     fs,
+    path::PathBuf,
     sync::Arc,
     thread,
 };
@@ -108,7 +109,7 @@ pub struct AppData {
     capture_filter: CaptureFilter,
     captures: RefCell<HashMap<CaptureSource, Arc<Capture>>>,
     dmabuf_feedback: Option<DmabufFeedback>,
-    gbm: Option<gbm::Device<fs::File>>,
+    gbm: Option<(PathBuf, gbm::Device<fs::File>)>,
 }
 
 impl AppData {

src/wayland/screencopy.rs

@@ -34,7 +34,10 @@ impl ScreencopyHandler for AppData {
         }
         let buffer = buffer.as_ref().unwrap();
 
-        session.attach_buffer(&buffer.buffer, None, 0); // XXX age?
+        let node = buffer
+            .node()
+            .and_then(|x| x.to_str().map(|x| x.to_string()));
+        session.attach_buffer(&buffer.buffer, node, 0); // XXX age?
         if capture.first_frame() {
             session.commit(zcosmic_screencopy_session_v1::Options::empty());
         } else {