display-manager: systemd-udev-settle serves no purpose, boot 10% faster #25311

peterhoeg · 2017-04-29T03:34:49Z

Motivation for this change

systemd-udev-settle.service is a leftover from a time when it was possible to say "now all the hardware I will ever need has shown up" and really doesn't make sense in the very dynamic world of today. Additionally is slows down boot by about 1.2 seconds on the hardware I have available.

Yet it is pulled in by the following units:

$ ag udev-settle | grep -i -e req -e want

nixos/modules/services/hardware/brltty.nix:42:     wants = [ "systemd-udev-settle.service" ];
nixos/modules/services/scheduling/atd.nix:73:      wants = [ "systemd-udev-settle.service" ];
nixos/modules/services/x11/xserver.nix:528:        wants = [ "systemd-udev-settle.service" ];
nixos/modules/tasks/filesystems/zfs.nix:338:       requires = [ "systemd-udev-settle.service" ];

I don't have any experience with braille displays or ZFS to say if it is truly needed here so I have left these out, but for atd and display-manager it's pointless.

It's tested here on 2 physical machines (a regular desktop and a laptop with a dm-crypt encrypted home) and apart from the improvement in boot speed there is no difference.

All units with default dependencies (ie without DefaultDependencies=no) get an implicit After=basic.target which implies After=local-fs.target so that's why I ripped that out of
display-manager.service while at it.

Things done

Tested using sandboxing
(nix.useSandbox on NixOS,
or option build-use-sandbox in nix.conf
on non-NixOS)
Built on platform(s)
- NixOS
- macOS
- Linux
Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
Tested execution of all binary files (usually in ./result/bin/)
Fits CONTRIBUTING.md.

mention-bot · 2017-04-29T03:34:52Z

@peterhoeg, thanks for your PR! By analyzing the history of the files in this pull request, we identified @edolstra, @nbp and @peti to be potential reviewers.

Mic92 · 2017-04-29T05:59:05Z

For ZFS in general this is sadly still required until something like this is merged: openzfs/zfs#4943 (at least in RAID systems)

peterhoeg · 2017-04-29T06:55:33Z

We should probably just leave zfs alone for now then.

According to git blame, @abbradar and @edolstra were the last to touch the lines related to systemd-udev-settle in xserver.nix. Any thoughts on this?

rnhmjoj · 2017-04-29T13:18:08Z

A few months ago after playing with systemd-analyze I noticed it was slowing down the boot considerably. Since I don't use LVM or ZFS and I masked it out and had no problems so far.

peterhoeg · 2017-04-30T07:25:05Z

So this is what I have tested so far:

boot from LVM and using dm-crypt on laptop
boot from just an SSD on desktop
boot from LVM on software RAID 6 on NAS

Everything is working as normal.

abbradar · 2017-04-30T15:47:56Z

I agree with the idea -- display-manager doesn't likely need udev settle now. Have you tested that atd works?

peterhoeg · 2017-05-01T09:35:48Z

@abbradar, atd is related to executing stuff at a later point in time
and has nothing to do with getting early boot ready, so I cannot for the life of
me imagine why it would need it.

Mic92 · 2017-05-01T09:57:01Z

This dependency was added to atd as a result of the transformation from upstart to systemd: peterhoeg@88292fd#diff-8b2f21139e43cda61f9c03ea3f65d9f4L72

However I think jobs relying on hardware initialization should add this dependency on its own.

edolstra · 2017-05-01T11:12:32Z

Actually I added the dependency in display-manager pretty recently, to fix an X server startup failure: e6bcff4. So the issue in that commit would have to be addressed first.

edolstra · 2017-05-01T11:14:03Z

Dropping the dependency in atd seems unproblematic.

peterhoeg · 2017-05-01T14:59:56Z

@edolstra, the failed test was related to kde4 which has been dropped. Running nix-build nixos/tests/{plasma5,sddm,xfce}.nix works here.

Mic92 · 2017-05-06T06:44:31Z

If the device /dev/dri/card0 is really required, it could be also a .device dependency of display-manager. However I did not find any indication, that this is required. In the following I show the upstream .service files of the display-manager we use:

#gdm
[Unit]
Description=GNOME Display Manager

# replaces the getty
[email protected]
[email protected]

# replaces plymouth-quit since it quits plymouth on its own
Conflicts=
After=

# Needs all the dependencies of the services it's replacing
# pulled from [email protected] and
# (except for plymouth-quit-wait.service since it waits until
# plymouth is quit, which we do)
After=rc-local.service plymouth-start.service systemd-user-sessions.service

# GDM takes responsibility for stopping plymouth, so if it fails
# for any reason, make sure plymouth still stops
OnFailure=plymouth-quit.service

[Service]
ExecStart=/usr/bin/gdm
KillMode=mixed
Restart=always
IgnoreSIGPIPE=no
BusName=org.gnome.DisplayManager
StandardOutput=syslog
StandardError=inherit
EnvironmentFile=-/etc/locale.conf

[Install]
Alias=display-manager.service

[Unit]
Description=Simple Desktop Display Manager
Documentation=man:sddm(1) man:sddm.conf(5)
[email protected]
After=systemd-user-sessions.service [email protected] plymouth-quit.service

[Service]
ExecStart=/usr/bin/sddm
Restart=always

[Install]
Alias=display-manager.service

[Unit]
Description=SLiM Simple Login Manager
After=systemd-user-sessions.service

[Service]
ExecStart=/usr/bin/slim -nodaemon
Restart=on-failure

[Install]
Alias=display-manager.service

# lightdm
[Unit]
Description=Light Display Manager
Documentation=man:lightdm(1)
[email protected]
[email protected] systemd-user-sessions.service plymouth-quit.service acpid.service

[Service]
ExecStart=/usr/bin/lightdm
Restart=always
IgnoreSIGPIPE=no
BusName=org.freedesktop.DisplayManager

[Install]
Alias=display-manager.service

peterhoeg · 2017-05-07T03:25:13Z

I think the issue is that technically the display manager is prone to a race condition but in the vast majority of cases, udev manages to create the device node in time. There is a similar bug on ubuntu but regarding lightdm: https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/969489

We cannot simply do wants = [ "dev-dri-card0.device" ]; as we need udev to tag the device nodes in order to show up as "wantable" for systemd.

In my opinion, we should merge this and then start looking at the udev tagging in case we see odd test failures again - remember that kde5, sddm and xfce tests are passing with this change.

peterhoeg · 2017-05-07T11:29:52Z

Unless @edolstra has any concerns, I'll go ahead and merge this.

edolstra · 2017-05-08T09:43:00Z

I object given that the race in e6bcff4 hasn't been fixed AFAIK. Saying that in the vast majority of cases udev creates the device nodes in time, well, that's the essence of race conditions. IIRC, in my case, the X server failed to start about a third of the time, which is not acceptable.

peterhoeg · 2017-05-08T09:51:00Z

I tried doing "reproduce locally" and the test failed (the kde4 test).
I also did nix-build nixos/tests/{plasma5,sddm,xfce}.nix locally and it succeeded every time.

So whatever was causing the kde4 test to fail, doesn't seem to be affecting the other DEs.

vcunat · 2017-05-10T10:42:12Z

If the main advantage is supposed to be booting faster by about one second, it doesn't really seem worth the risk to me. Still, I might be biased due to often running for weeks without a reboot.

peterhoeg · 2017-05-14T09:10:22Z

the main advantage is supposed to be booting faster by about one second

It isn't - it's just a positive sideeffect. If it was, I would fully agree with you.

Running udev-settle is just the wrong way to go around it as all parts dependent on various devices should be able to declare their dependency. As we are not there quite yet, udev-settle was introduced but it was meant as a temporary solution.

The nixos tests are working here and I have been running with this change for a week or so without any problems.kk

Ekleog · 2018-10-18T01:17:24Z

(triage) If I understand correctly, this is currently blocked on the race condition issue for e6bcff4 being solved… but now, it looks like KDE4 support has been dropped. Is it still necessary to block this on a race condition that no one can exhibit, and maybe no longer exists?

peterhoeg · 2018-10-18T06:56:10Z

I'm all for merging this but I think I'm pretty alone with that... ;-)

rnhmjoj · 2018-10-18T07:37:40Z

I have disabled udev-settle on all my devices more than a year ago and found no particular issue.
What's the status of udev tags?

Mic92 · 2018-10-18T17:37:43Z

I did the same as @rnhmjoj. It also no longer required for zfs, where have different ways to ensure all devices are present.

pmiddend · 2018-10-18T18:03:23Z

Sorry for the stupid question, but: can I just disable the service and NixOS will not re-enable it?

Mic92 · 2018-10-18T18:06:34Z

@pmiddend you can put the following in your configuration:

https://github.com/Mic92/dotfiles/blob/f07c63d715c949b0831ea50653f6e002cf8c7bcb/nixos/vms/modules/networkd.nix#L9

peterhoeg · 2018-10-19T03:38:05Z

An alternative is of course to make it configurable and instead of removing the reference to the unit, simply zero it out like @Mic92 suggests (which is what I have been using on this side as well).

Mic92 · 2018-10-19T07:22:46Z

It also sometimes fail to restart on upgrade, so we might don't want to restart it when we upgrade at all.

mmahut · 2019-08-09T07:16:35Z

Any updates on this pull request, please?

nixos-discourse · 2020-03-20T16:00:50Z

This pull request has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/boot-faster-by-disabling-udev-settle-and-nm-wait-online/6339/1

peterhoeg · 2020-03-21T04:11:26Z

the display manager issue no longer applies as kde4 has been dropped
the atd bit is straight forward
the zfs part is purely documentation

So in my book this is completely safe to merge. Unless somebody puts up some resistance I'm going to go ahead and do that in a few days time.

The other part of this is that there are still a number of services that pull this in, so the safest way if you don't want/need it is to disable systemd-udev-settle completely. Of course that doesn't mean we shouldn't clean things up.

nixos/tests/misc.nix:2
nixos/modules/config/console.nix:1
nixos/modules/hardware/ksm.nix:1
nixos/modules/security/lock-kernel-modules.nix:1
nixos/modules/virtualisation/anbox.nix:1
nixos/modules/virtualisation/libvirtd.nix:1
nixos/modules/virtualisation/openvswitch.nix:1
nixos/modules/virtualisation/lxd.nix:1
nixos/modules/services/hardware/acpid.nix:1
nixos/modules/services/hardware/brltty.nix:2
nixos/modules/services/hardware/tcsd.nix:1
nixos/modules/services/hardware/trezord.nix:1
nixos/modules/services/scheduling/atd.nix:2
nixos/modules/services/networking/dhcpcd.nix:2
nixos/modules/services/x11/xserver.nix:2
nixos/modules/system/boot/networkd.nix:2
nixos/modules/system/boot/systemd.nix:2
nixos/modules/tasks/filesystems/zfs.nix:2

jtojnar · 2020-04-05T13:33:40Z

This seems to have broken GDM:

https://hydra.nixos.org/build/115957916/nixlog/11

Which blocks the channel.

$ nix-build nixos/release-combined.nix -A nixos.tests.gnome3-xorg.x86_64-linux
[...]
machine # [   17.140888] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: X.Org X Server 1.20.7
machine # [   17.143516] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: X Protocol Version 11, Revision 0
machine # [   17.147588] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: Build Operating System: Linux 4.19.69 x86_64
machine # [   17.150918] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: Current Operating System: Linux machine 5.4.30 #1-NixOS SMP Thu Apr 2 13:11:03 UTC 2020 x86_64
machine # [   17.155097] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: Kernel command line: console=ttyS0 panic=1 boot.panic_on_fail loglevel=7 net.ifnames=0 init=/nix/store/l3ylsc8lbp6jiyzg0fzknc24a9dvvxr4-nixos-system-machine-20.09.git.8470272d3cc/init regInfo=/nix/store/x74fkam44q3d4whm1r31yrp69faxmzma-closure-info/registration console=ttyS0
machine # [   17.161325] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: Build Date: 13 January 2020  10:57:44PM
machine # [   17.165718] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:
machine # [   17.171667] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: Current version of pixman: 0.38.4
machine # [   17.175953] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     Before reporting problems, check http://wiki.x.org
machine # [   17.181454] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     to make sure that you have the latest version.
machine # [   17.185099] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: Markers: (--) probed, (**) from config file, (==) default setting,
machine # [   17.189133] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     (++) from command line, (!!) notice, (II) informational,
machine # [   17.193325] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
machine # [   17.197645] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (++) Log file: "/dev/null", Time: Sun Apr  5 13:28:34 2020
machine # [   17.203904] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (++) Using config file: "/nix/store/6in2hhmm6qlbc22d2c12qm6lsr4yj279-xserver.conf"
machine # [   17.211724] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (==) Using config directory: "/etc/X11/xorg.conf.d"
machine # [   17.217389] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (==) Using system config directory "/nix/store/s5mji17miyfq819i5qmdb79dpp0qlcvm-xorg-server-1.20.7/share/X11/xorg.conf.d"
machine # [   17.222528] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (==) ServerLayout "Layout[all]"
machine # [   17.225627] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (**) |-->Screen "Screen-modesetting[0]" (0)
machine # [   17.229970] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (**) |   |-->Monitor "Monitor[0]"
machine # [   17.236651] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (**) |   |-->Device "Device-modesetting[0]"
machine # [   17.247044] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (**) Option "DontZap" "on"
machine # [   17.255692] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (**) Option "AllowMouseOpenFail" "on"
machine # [   17.262344] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (==) Automatically adding devices
machine # [   17.265737] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (==) Automatically enabling devices
machine # [   17.272391] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (==) Automatically adding GPU devices
machine # [   17.283035] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (==) Max clients allowed: 256, resource mask: 0x1fffff
machine # [   17.318474] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (**) FontPath set to:
machine # [   17.330109] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     /nix/store/5dc4zibj1ddr240i5sw64kk0byjb9l1h-font-bh-lucidatypewriter-100dpi-1.0.3/lib/X11/fonts/100dpi,
machine # [   17.334627] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     /nix/store/4shq5nnpdli1xf62z2s25jns5z1k6sfl-font-bh-lucidatypewriter-75dpi-1.0.3/lib/X11/fonts/75dpi,
machine # [   17.339608] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     /nix/store/3mh58v3rsygp99rw68g3f3ifzjs2sadz-font-bh-100dpi-1.0.3/lib/X11/fonts/100dpi,
machine # [   17.343466] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     /nix/store/6vjpny9hkigm4qbn5w0kzlxh29z4r8yh-font-misc-misc-1.1.2/lib/X11/fonts/misc,
machine # [   17.349916] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     /nix/store/3274clsg5h9zqy8828gvygadn40nhar8-font-cursor-misc-1.0.3/lib/X11/fonts/misc,
machine # [   17.359525] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     /nix/store/iaknszix9ql8vxbvvxbxzp1q1lph7gpi-unifont-13.0.01/share/fonts,
machine # [   17.367275] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     /nix/store/rdgigqgqlkb27pvxkqj2xxjdfaaqq9id-font-adobe-100dpi-1.0.3/lib/X11/fonts/100dpi,
machine # [   17.378773] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     /nix/store/c5mpwb43xazg4chhhvy38ngakdrm5gw4-font-adobe-75dpi-1.0.3/lib/X11/fonts/75dpi
machine # [   17.382929] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (**) ModulePath set to "/nix/store/s5mji17miyfq819i5qmdb79dpp0qlcvm-xorg-server-1.20.7/lib/xorg/modules,/nix/store/s5mji17miyfq819i5qmdb79dpp0qlcvm-xorg-server-1.20.7/lib/xorg/modules/drivers,/nix/store/s5mji17miyfq819i5qmdb79dpp0qlcvm-xorg-server-1.20.7/lib/xorg/modules/extensions,/nix/store/4bw9v8nn9p648y3di31xyfbs0p1zxbfm-xf86-input-evdev-2.10.6/lib/xorg/modules/input,/nix/store/14rbssgxb87ajmsvv6y2g0l3hfzk75nq-xf86-input-libinput-0.28.2/lib/xorg/modules/input"
machine # [   17.390869] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) The server relies on udev to provide the list of input devices.
machine # [   17.394829] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     If no devices become available, reconfigure udev or disable AutoAddDevices.
machine # [   17.399152] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) Loader magic: 0x625d40
machine # [   17.405842] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) Module ABI versions:
machine # [   17.413073] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     X.Org ANSI C Emulation: 0.4
machine # [   17.415613] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     X.Org Video Driver: 24.1
machine # [   17.418389] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     X.Org XInput driver : 24.1
machine # [   17.422688] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     X.Org Server Extension : 10.0
machine # [   17.426714] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (++) using VT number 2
machine # [   17.431033] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) systemd-logind: took control of session /org/freedesktop/login1/session/_31
machine # [   17.439615] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) xfree86: Adding drm device (/dev/dri/card0)
machine # [   17.445366] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (EE) systemd-logind: failed to take device /dev/dri/card0: Operation not permitted
machine # [   17.448492] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (--) PCI:*(0@0:2:0) 1234:1111:1af4:1100 rev 2, Mem @ 0xfd000000/16777216, 0xfebd0000/4096, BIOS @ 0x????????/131072
machine # [   17.452309] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (WW) Open ACPI failed (/var/run/acpid.socket) (No such file or directory)
machine # [   17.459858] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) "glx" will be loaded by default.
machine # [   17.464961] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) LoadModule: "glx"
machine # [   17.471026] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) Loading /nix/store/s5mji17miyfq819i5qmdb79dpp0qlcvm-xorg-server-1.20.7/lib/xorg/modules/extensions/libglx.so
machine # [   17.478897] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) Module glx: vendor="X.Org Foundation"
machine # [   17.482470] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     compiled for 1.20.7, module version = 1.0.0
machine # [   17.485577] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     ABI class: X.Org Server Extension, version 10.0
machine # [   17.489428] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) LoadModule: "modesetting"
machine # [   17.495415] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) Loading /nix/store/s5mji17miyfq819i5qmdb79dpp0qlcvm-xorg-server-1.20.7/lib/xorg/modules/drivers/modesetting_drv.so
machine # [   17.509446] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) Module modesetting: vendor="X.Org Foundation"
machine # [   17.514422] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     compiled for 1.20.7, module version = 1.20.7
machine # [   17.517535] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     Module class: X.Org Video Driver
machine # [   17.520950] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     ABI class: X.Org Video Driver, version 24.1
machine # [   17.525011] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modesetting: Driver for Modesetting Kernel Drivers: kms
machine # [   17.529210] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): using drv /dev/dri/card0
machine # [   17.532207] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (WW) VGA arbiter: cannot open kernel arbiter, no multi-card support
machine # [   17.536743] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (==) modeset(0): Depth 24, (==) framebuffer bpp 32
machine # [   17.545573] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (==) modeset(0): RGB weight 888
machine # [   17.548972] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (==) modeset(0): Default visual is TrueColor
machine # [   17.552693] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) Loading sub module "glamoregl"
machine # [   17.557371] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) LoadModule: "glamoregl"
machine # [   17.559999] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) Loading /nix/store/s5mji17miyfq819i5qmdb79dpp0qlcvm-xorg-server-1.20.7/lib/xorg/modules/libglamoregl.so
machine # [   17.598043] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) Module glamoregl: vendor="X.Org Foundation"
machine # [   17.601790] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     compiled for 1.20.7, module version = 1.0.1
machine # [   17.605138] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     ABI class: X.Org ANSI C Emulation, version 0.4
machine # [   17.608512] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: pci id for fd 14: 1234:1111, driver (null)
machine # [   19.080437] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Refusing to try glamor on llvmpipe
machine # [   19.231853] broken atomic modeset userspace detected, disabling atomic
machine # [   19.092729] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (EE) modeset(0): glamor initialization failed
machine # [   19.095682] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): ShadowFB: preferred NO, enabled NO
machine # [   19.103837] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Output Virtual-1 using monitor section Monitor[0]
machine # [   19.108119] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): EDID for output Virtual-1
machine # [   19.111067] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Manufacturer: RHT  Model: 1234  Serial#: 0
machine # [   19.115056] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Year: 2014  Week: 42
machine # [   19.121926] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): EDID Version: 1.4
machine # [   19.125732] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Digital Display Input
machine # [   19.129971] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): 8 bits per channel
machine # [   19.134119] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Digital interface is DisplayPort
machine # [   19.141644] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Max Image Size [cm]: horiz.: 40  vert.: 30
machine # [   19.163062] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Gamma: 2.20
machine # [   19.166036] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): No DPMS capabilities specified
machine # [   19.169215] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Supported color encodings: RGB 4:4:4
machine # [   19.172304] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Default color space is primary color space
machine # [   19.175539] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): First detailed timing is preferred mode
machine # [   19.180156] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Preferred mode is native pixel format and refresh rate
machine # [   19.186925] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): redX: 0.640 redY: 0.330   greenX: 0.300 greenY: 0.600
machine # [   19.193630] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): blueX: 0.150 blueY: 0.060   whiteX: 0.312 whiteY: 0.329
machine # [   19.197118] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Supported established timings:
machine # [   19.199879] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): 640x480@60Hz
machine # [   19.202574] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): 800x600@60Hz
machine # [   19.205399] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): 1024x768@60Hz
machine # [   19.208150] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Manufacturer's mask: 0
machine # [   19.215429] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Supported standard timings:
machine # [   19.221849] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): #0: hsize: 2048  vsize 1152  refresh: 60  vid: 49377
machine # [   19.227936] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): #1: hsize: 1920  vsize 1080  refresh: 60  vid: 49361
machine # [   19.231680] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Supported detailed timing:
machine # [   19.235137] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): clock: 82.3 MHz   Image Size:  403 x 302 mm
machine # [   19.239264] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): h_active: 1024  h_sync: 1280  h_sync_end 1310 h_blank_end 1382 h_border: 0
machine # [   19.244544] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): v_active: 768  v_sync: 771  v_sync_end 774 v_blanking: 794 v_border: 0
machine # [   19.250791] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Ranges: V min: 50 V max: 125 Hz, H min: 30 H max: 160 kHz, PixClock max 1205 MHz
machine # [   19.261588] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Monitor name: QEMU Monitor
machine # [   19.265270] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Established timings III: (not decoded)
machine # [   19.268896] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Number of EDID sections to follow: 1
machine # [   19.275877] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): EDID (in hex):
machine # [   19.288062] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0):    00ffffffffffff004914341200000000
machine # [   19.297321] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0):    2a180104a5281e7806ee91a3544c9926
machine # [   19.304877] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0):    0f5054210800e1c0d1c0010101010101
machine # [   19.331737] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0):    0101010101012520006641001a30001e
machine # [   19.381549] gdm-autologin][842]: pam_unix(gdm-autologin:session): session closed for user alice
machine # [   19.392917] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0):    3340932e11000018000000fd00327d1e
machine # [   19.398721] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0):    a078010a202020202020000000fc0051
machine # [   19.404675] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0):    454d55204d6f6e69746f720a000000f7
machine # [   19.417317] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0):    000a004aa22429200000000000000119
machine # [   19.421353] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0):    02030a00457d6560591f000000000000
machine # [   19.426419] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0):    00000000000000000000000000000000
machine # [   19.429660] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0):    00000000000000000000000000000000
machine # [   19.432455] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0):    00000000000000000000000000000000
machine # [   19.436053] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0):    00000000000000000000000000000000
machine # [   19.440470] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0):    00000000000000000000000000000000
machine # [   19.446097] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0):    00000000000000000000000000000000
machine # [   19.449974] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0):    000000000000000000000000000000f2
machine # [   19.452835] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Printing probed modes for output Virtual-1
machine # [   19.455659] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Modeline "1024x768"x75.0   82.29  1024 1280 1310 1382  768 771 774 794 -hsync -vsync (59.5 kHz UeP)
machine # [   19.459371] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Modeline "1920x1080"x60.0  148.50  1920 2008 2052 2200  1080 1084 1089 1125 -hsync -vsync (67.5 kHz e)
machine # [   19.463772] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Modeline "1920x1080"x50.0  148.50  1920 2448 2492 2640  1080 1084 1089 1125 +hsync +vsync (56.2 kHz e)
machine # [   19.468467] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Modeline "1600x1200"x60.0  162.00  1600 1664 1856 2160  1200 1201 1204 1250 +hsync +vsync (75.0 kHz e)
machine # [   19.473987] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Modeline "1680x1050"x60.0  146.25  1680 1784 1960 2240  1050 1053 1059 1089 -hsync +vsync (65.3 kHz e)
machine # [   19.480962] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Modeline "1400x1050"x60.0  121.75  1400 1488 1632 1864  1050 1053 1057 1089 -hsync +vsync (65.3 kHz e)
machine # [   19.484489] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Modeline "1280x1024"x60.0  108.00  1280 1328 1440 1688  1024 1025 1028 1066 +hsync +vsync (64.0 kHz e)
machine # [   19.487570] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Modeline "1440x900"x59.9  106.50  1440 1520 1672 1904  900 903 909 934 -hsync +vsync (55.9 kHz e)
machine # [   19.490515] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Modeline "1280x960"x60.0  108.00  1280 1376 1488 1800  960 961 964 1000 +hsync +vsync (60.0 kHz e)
machine # [   19.493634] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Modeline "1360x768"x60.0   85.50  1360 1424 1536 1792  768 771 777 795 +hsync +vsync (47.7 kHz e)
machine # [   19.497770] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Modeline "1280x768"x59.9   79.50  1280 1344 1472 1664  768 771 778 798 -hsync +vsync (47.8 kHz e)
machine # [   19.504752] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Modeline "1024x768"x60.0   65.00  1024 1048 1184 1344  768 771 777 806 -hsync -vsync (48.4 kHz e)
machine # [   19.510363] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Modeline "800x600"x60.3   40.00  800 840 968 1056  600 601 605 628 +hsync +vsync (37.9 kHz e)
machine # [   19.515226] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Modeline "640x480"x60.0   25.20  640 656 752 800  480 490 492 525 -hsync -vsync (31.5 kHz e)
machine # [   19.518334] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Modeline "640x480"x59.9   25.18  640 656 752 800  480 490 492 525 -hsync -vsync (31.5 kHz e)
machine # [   19.521330] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Output Virtual-1 connected
machine # [   19.523537] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Using user preference for initial modes
machine # [   19.526126] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) modeset(0): Output Virtual-1 using initial mode 1024x768 +0+0
machine # [   19.529095] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (==) modeset(0): Using gamma correction (1.0, 1.0, 1.0)
machine # [   19.532496] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (==) modeset(0): DPI set to (96, 96)
machine # [   19.537388] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) Loading sub module "fb"
machine # [   19.541130] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) LoadModule: "fb"
machine # [   19.545439] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) Loading /nix/store/s5mji17miyfq819i5qmdb79dpp0qlcvm-xorg-server-1.20.7/lib/xorg/modules/libfb.so
machine # [   19.548477] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (II) Module fb: vendor="X.Org Foundation"
machine # [   19.550699] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     compiled for 1.20.7, module version = 1.0.0
machine # [   19.552972] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:     ABI class: X.Org ANSI C Emulation, version 0.4
machine # [   19.555371] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (EE) modeset(0): drmSetMaster failed: Permission denied
machine # [   19.558677] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (EE)
machine # [   19.561022] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: Fatal server error:
machine # [   19.565043] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (EE) AddScreen/ScreenInit failed for driver 0
machine # [   19.569928] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (EE)
machine # [   19.574757] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (EE)
machine # [   19.578702] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: Please consult the The X.Org Foundation support
machine # [   19.581434] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:      at http://wiki.x.org
machine # [   19.583401] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]:  for help.
machine # [   19.585129] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (EE) Please also check the log file at "/dev/null" for additional information.
machine # [   19.587877] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (EE)
machine # [   19.589690] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: (EE) Server terminated with error (1). Closing log file.
machine # [   19.593475] /nix/store/m2xfn00ry7vlys3i4y3pkw9jjskjyq0y-gdm-3.34.1/libexec/gdm-x-session[863]: Unable to run X server

peterhoeg · 2020-04-05T14:16:09Z

This seems to have broken GDM:

And if you do a `git revert 7f838b4`?

jtojnar · 2020-04-05T14:20:35Z

Yup, reverting that fixes the issue. Maybe we can just add it to gdm.nix.

peterhoeg · 2020-04-05T14:34:13Z

Maybe we can just add it to gdm.nix.

Sounds like a good workaround. The proper fix is to have udev tag the DRI device for systemd use and then set up wants/after on the DRI device.

jtojnar · 2020-04-05T14:41:39Z

Pushed f74f2f3 since I am not well versed in systemd/udev stuff.

Possibly relevant: systemd/systemd#14504

peterhoeg · 2020-04-05T14:53:51Z

Commenting on your commit message, we are not actually doing anything wrong. We have a race condition, where gdm starts up before udev has had the time to properly set permissions on the /dev/dri/card0 device. By using 'systemd-udev-settle', we are a introducing an artificial delay that allows it catch up and do its thing. I believe the gnome guys are working on a proper way to handle this (have gdm wait for things to be OK instead of throwing a hissyfit). If we introduce ordering, we will not hit the race condition. Another way we can probably work around this is by having the `drm` kernel module loaded early as part of the initramfs but again, we really are just masking the issue.

jtojnar · 2020-04-05T21:44:07Z

But display-manager.service should already run After systemd-logind.service, which contains:

ExecStartPre=-/nix/store/ijka1p5ndsjq60frdhlq5il0s9mgyypj-kmod-26/sbin/modprobe -abq drm

I would expect that to work, unless we are affected by systemd/systemd#14322.

peterhoeg · 2020-04-07T13:17:25Z

ExecStartPre=-/nix/store/ijka1p5ndsjq60frdhlq5il0s9mgyypj-kmod-26/sbin/modprobe -abq drm

That might not be enough depending on how long it takes to initialize. It looks like the only *proper* way to fix it is a dependency on the device as that means udev is done doing its thing. I hope to find some time to deal with this later in the week.

peterhoeg · 2020-04-07T13:17:53Z

That is, unless someone beats me to it (hint, hint)

domenkozar · 2021-03-18T10:09:18Z

I'm getting open /dev/dri/card0: No such file or directory on 20.09 but it works on 21.03 (da32a98), are we missing a backport?

EDIT: see #73095 (comment)

hmenke · 2021-09-22T20:03:05Z

Is this still a thing? In the journal I see

systemd-udev-settle.service is deprecated. Please fix display-manager.service not to pull it in.

rnhmjoj · 2021-09-22T20:27:58Z

Look at #73095 (comment)
Basically ZFS is the only module still using it.

peterhoeg changed the title ~~display-manager: systemd-udev-settle serves no purpose, boot 1.5s faster~~ display-manager: systemd-udev-settle serves no purpose, boot 1.2s faster Apr 29, 2017

peterhoeg changed the title ~~display-manager: systemd-udev-settle serves no purpose, boot 1.2s faster~~ display-manager: systemd-udev-settle serves no purpose, boot 10% faster Apr 29, 2017

peterhoeg force-pushed the f/udev-settle branch from b07c0a7 to 15c57e6 Compare May 7, 2017 06:02

Mic92 approved these changes May 7, 2017

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worldofpeace mentioned this pull request Nov 9, 2019

systemd-udev-settle.service is overused #73095

Closed

peterhoeg added 3 commits March 21, 2020 11:15

atd: systemd-udev-settle serves no purpose

53a51f2

zfs: document systemd-udev-settle dependency

8a31cf1

display-manager: systemd-udev-settle serves no purpose

7f838b4

peterhoeg force-pushed the f/udev-settle branch from 15c57e6 to 7f838b4 Compare March 21, 2020 03:16

matthewbauer approved these changes Mar 23, 2020

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peterhoeg merged commit 1859f12 into NixOS:master Mar 28, 2020

peterhoeg deleted the f/udev-settle branch March 28, 2020 13:24

Mic92 mentioned this pull request Apr 6, 2020

ZFS: Should use zfs-mount-generator instead of udev #84447

Closed

peterhoeg mentioned this pull request Dec 22, 2020

nixos/{networkd,dhcpcd}: remove udev-settle hack #107382

Merged

5 tasks

display-manager: systemd-udev-settle serves no purpose, boot 10% faster #25311

display-manager: systemd-udev-settle serves no purpose, boot 10% faster #25311

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peterhoeg commented Apr 29, 2017

Motivation for this change

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