[gdm/benzea/wait-for-udev: 2/2] data: Wait for systemd-udev-settle.service

[Benjamin Berg <bberg src gnome org>]

commit a8f24343d699698ebc5af712c44f019aa856c05c
Author: Benjamin Berg <bberg redhat com>
Date:   Mon Feb 8 15:18:58 2021 +0100

    data: Wait for systemd-udev-settle.service
    
    While technically deprecated, we really need to have the drm devices
    resolved when we try to start GNOME Shell. This is the straight forward
    way of ensuring that is the case.
    
    It might be possible to be a bit smarter here by watching udev and
    checking whether a DRM device is available for each seat.
    
    Closes: #662

 data/gdm.service.in | 8 ++++++++
 1 file changed, 8 insertions(+)
---
diff --git a/data/gdm.service.in b/data/gdm.service.in
index fbbfb529f..ae054b1f4 100644
--- a/data/gdm.service.in
+++ b/data/gdm.service.in
@@ -15,6 +15,14 @@ After=${PLYMOUTH_QUIT_SERVICE}
 # plymouth is quit, which we do)
 After=rc-local.service plymouth-start.service systemd-user-sessions.service
 
+# In order to start GNOME Shell (or the X server), we need the DRM device to
+# be available. However, when GDM starts the graphics driver may not be done
+# probing.
+# As such, delay until after systemd-udev-settle.service. Ideally we would only
+# wait for the seat to have a DRM device(/output) assigned.
+Wants=systemd-udev-trigger.service systemd-udev-settle.service
+After=systemd-udev-trigger.service systemd-udev-settle.service
+
 # GDM takes responsibility for stopping plymouth, so if it fails
 # for any reason, make sure plymouth still stops
 OnFailure=plymouth-quit.service