Need to reboot twice each time for switching gpu

[liorlobel]

Hi, thanks for this awesome little program :)
I get this weird issue where each time I either disconnect or connect the eGPU I need to go through not only a shutdown but also a reboot.
I suspect this is an issue with lightdm as the egpu.service is running probably after the display-manager.service, so the startup is stuck, since it uses the old xorg.conf. In support of this, if I drop to a tty, kill lightdm and startx, I get to the DE.
I'm not sure about how to fix it and will be gratful for help.
Thanks,
Lior

[ewagner12]

I can't confirm this on Ubuntu 19.10 with lightdm. Are you using ubuntu or a different distro?

[liorlobel]

Yes, ubuntu mate 19.10

[ewagner12]

Ok looking at the code and how systemd works it seems like there's a bit of a race condition right now. My laptop is slow to boot so it doesn't load the display manager faster than the switch command executes. I guess your computer is a lot faster than mine. If you want to try a solution would be to add
Before=display-manager.service
to /etc/systemd/system/egpu.service

[hertg]

I've had this error too a while ago. But in my case, the problem was that the EGPU didn't connect fast enough so the script didn't recognize it. This is why this dirty workaround exists:

egpu-switcher/egpu-switcher

Lines 101 to 104 in 0cacc0a

	if [ $1 = "lspci" ]; then
	# giving your egpu some time to actually connect
	sleep 5s

This is most definitely a timing issue, but i can't reproduce it with my system. I remember that there also were less problems on my notebook after i disabled the Thunderbolt Security in the BIOS. (See my comment on Thread.io)

I think i already tried to add the Before=display-manager.service while developing, but it didn't help back then. Still worth another try tho :)

[xabolcs]

Type oneshot is better for egpu.service than simple (the default).

With simple in my override.conf (see systemctl edit) the ExecPost= command started earlier than the ExecStart ended.

[hertg]

Type oneshot is better for egpu.service than simple (the default).

Am I understanding it correctly that oneshot will block the startup until the script is finished, where simple does just run the script asynchronously, so that the display-manager might start while the script is still executing?

If that's correct, this would probably be the fix for this issue. (Would it still be good to define Before=display-manager.service, or would that be unnecessary?)

With simple in my override.conf (see systemctl edit) the ExecPost= command started earlier than the ExecStart ended.

I did not quite get what you mean by that.

[xabolcs]

I did not quite get what you mean by that.

I wanted to reuse the egpu-switcher's eGPU detection functionality to decide on what Display Manager should start. 😄

And instead of writing a dependent service, I just wrote an ExecStartPost= step "in" the egpu.service:

● egpu.service - EGPU Service
   Loaded: loaded (/etc/systemd/system/egpu.service; enabled; vendor preset: enabled)
  Drop-In: /etc/systemd/system/egpu.service.d
           └─override.conf
   Active: inactive (dead) since Fri 2019-11-08 19:49:47 CET; 57s ago
  Process: 2398 ExecStartPost=/mnt/data/data/DEV/PROJECTS/PRIVATE/systemd/egpu/set-display-manager.sh (code=exited, stat
  Process: 1026 ExecStart=/usr/bin/egpu-switcher switch auto (code=exited, status=0/SUCCESS)
  Process: 1008 ExecStartPre=/mnt/data/data/DEV/PROJECTS/PRIVATE/systemd/egpu/generate-checksum.sh (code=exited, status=
 Main PID: 1026 (code=exited, status=0/SUCCESS)

Nov 08 19:49:42 schorschbock-l egpu-switcher[1026]: [info] Using default argument for is_egpu_connected().
Nov 08 19:49:47 schorschbock-l egpu-switcher[1026]: [info] Automatically detecting if egpu is connected...  true
Nov 08 19:49:47 schorschbock-l egpu-switcher[1026]: [info] Create symlink /etc/X11/xorg.conf -> /etc/X11/xorg.conf.egpu
Nov 08 19:49:47 schorschbock-l set-display-manager.sh[2398]: /etc/X11/xorg.conf: OK
Nov 08 19:49:47 schorschbock-l set-display-manager.sh[2398]: Display Manager is lightdm already, nothing to see here!
Nov 08 19:49:47 schorschbock-l systemd[1]: Started EGPU Service.
Warning: Journal has been rotated since unit was started. Log output is incomplete or unavailable.

Am I understanding it correctly that oneshot ...

Yup.

From SystemD documentation:

ExecStartPost= commands are only run after the commands specified in ExecStart= have been invoked successfully, as determined by Type= (i.e. the process has been started for Type=simple or Type=idle, the last ExecStart= process exited successfully for Type=oneshot, the initial process exited successfully for Type=forking, "READY=1" is sent for Type=notify, or the BusName= has been taken for Type=dbus).

Btw, the automatic DM selection between LightDM (in eGPU mode) and GDM3 (in internal mode) isn't achieved yet: it needs a restart like in this issue. 😞

[hertg]

I just released a rather big update 0.11.1.
The egpu.service is now defined as Type=oneshot.
I hope that this resolves the issue, please feel free to open it again if the update didn't help with your problem. :)

[liorlobel]

Can confirm the issue is solved. Thanks so much :)

[eerozeteen]

Hi,
I had same issue with my Lenovo x230 @ Manjaro and Beast gdc egpu with Radeon HD7770. "Before=display-manager.service" in egpu.service solve it.
Please consider add it permanently.