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Elmario

Member

Registered: 2023-08-21

Posts: 72

[SOLVED] help with command for disabling dGPU not working from service

Hello!

I have an god awful Asus Zephyrus G14 'ThePain' Notebook with an additional 6800S dGPU.
The aim is to have the notebook running poer saving and making the hardware longlived, by not having the dGPU run all the time when it's not needed.

For doing so I have to use supergfxctl to switch the notebook to 'Hybrid' mode and then 'manually' disable the dPGU, because when using the 'Integrated' mode that's meant to run only using the iGPU, this trash notebook freezes all the time (Btw: It's a Linux problem, but finding a solution to this sadly is impossible for me)

So, for disabling the dGPU I use the follwing command:
'echo 1 > /sys/devices/platform/asus-nb-wmi/dgpu_disable'

For making it easier available and to also automatically applying this at boot, I created a systemd-unit  file, as you can see here:

GNU nano 8.4                                                                                                                 disabledGPU.service                                                                                                                             
[Unit]
Description=Disables dGPU when the service is enabled

[Service]
ExecStart=echo 1 > /sys/devices/platform/asus-nb-wmi/dgpu_disable
ExecStop=echo 0 > /sys/devices/platform/asus-nb-wmi/dgpu_disable

[Install]
WantedBy=multi-user.target

I enabled the service and manually started it. From systemctl status the services starts and rtuns the command without an error - but the content '/sys/devices/platform/asus-nb-wmi/dgpu_disable' does not change, no matter if I start or stop the service:

sudo systemctl status disabledGPU.service
Warning: The unit file, source configuration file or drop-ins of disabledGPU.service changed on disk. Run 'systemctl daemon-reload' to reload units.
○ disabledGPU.service - Disables dGPU when the service is enabled
     Loaded: loaded (/etc/systemd/system/disabledGPU.service; enabled; preset: disabled)
     Active: inactive (dead) since Sun 2025-06-01 14:06:27 CEST; 2min 43s ago
   Duration: 29ms
Invocation: c9cf7f9d7045417db1eeb1932306a202
    Process: 63145 ExecStart=echo 1 > /sys/devices/platform/asus-nb-wmi/dgpu_disable (code=exited, status=0/SUCCESS)
    Process: 63146 ExecStop=echo 0 > /sys/devices/platform/asus-nb-wmi/dgpu_disable (code=exited, status=0/SUCCESS)
   Main PID: 63145 (code=exited, status=0/SUCCESS)
   Mem peak: 1.7M
        CPU: 11ms

Jun 01 14:06:26 work systemd[1]: Started Disables dGPU when the service is enabled.
Jun 01 14:06:26 work echo[63145]: 1 > /sys/devices/platform/asus-nb-wmi/dgpu_disable
Jun 01 14:06:26 work echo[63146]: 0 > /sys/devices/platform/asus-nb-wmi/dgpu_disable
Jun 01 14:06:27 work systemd[1]: disabledGPU.service: Deactivated successfully.

Can someone please tell me what's wrong here?`:)

Last edited by Elmario (2025-06-01 13:58:59)

Scimmia

Fellow

Registered: 2012-09-01

Posts: 12,829

Re: [SOLVED] help with command for disabling dGPU not working from service

'>' is a redirect interpreted by the shell. You don't have a shell here.

Elmario

Member

Registered: 2023-08-21

Posts: 72

Re: [SOLVED] help with command for disabling dGPU not working from service

OK, I have the "echo part" working like this:

  GNU nano 8.4                                            disabledGPU.service                                                       
[Unit]
Description=Disables dGPU when the service is enabled

[Service]
ExecStart=bash -c "echo 1 > /sys/devices/platform/asus-nb-wmi/dgpu_disable"
ExecStop=bash -c "echo 0 > /sys/devices/platform/asus-nb-wmi/dgpu_disable"

[Install]
WantedBy=multi-user.target

Thanks for your help.
Now there's another issue with the  unit: It always executes both commands (ExecStart and ExecStop) at once, so the result always 0 . That's not how I thought it would be working ..

Last edited by Elmario (2025-06-01 13:51:04)

Scimmia

Fellow

Registered: 2012-09-01

Posts: 12,829

Re: [SOLVED] help with command for disabling dGPU not working from service

simplest would probably be to use bash -c 'command'. Then you can use all features of bash, including the redirect.'

The next thing you're going to run into, though, is that the command executes, finishes, and the service stops. You will need to sleep or something.

Last edited by Scimmia (2025-06-01 13:52:39)

Elmario

Member

Registered: 2023-08-21

Posts: 72

Re: [SOLVED] help with command for disabling dGPU not working from service

Hello, sorry. I have the bad habit in editing my posts countless times - I just found the "bash -c" workaround, too, thank you!

Now the next issue is, that everytime I start the service, actually both commands are run: ExecStart and ExecStop. Shouldn't ExecStop just run when I stop the service?
Edit:
I found the solution to this:

[Unit]
Description=Disables dGPU when the service is enabled

[Service]
Type=oneshot
ExecStart=bash -c "echo 1 > /sys/devices/platform/asus-nb-wmi/dgpu_disable"
RemainAfterExit=true
ExecStop=bash -c "echo 0 > /sys/devices/platform/asus-nb-wmi/dgpu_disable"

I also had to remove the target from the service-unit and create an additional timer instead, because otherwise the command would be executed too early in theboot process and in advance got overriden by something else:

GNU nano 8.4                                                                                                        /etc/systemd/system/disabledGPU.timer                                                                                                                   
[Timer]
OnBootSec=1min

[Install]
WantedBy=graphical.target

Also it's needed to disable the service itself, but enable the timer.

Thank you very much!

Last edited by Elmario (2025-06-01 14:21:35)

Scimmia

Fellow

Registered: 2012-09-01

Posts: 12,829

Re: [SOLVED] help with command for disabling dGPU not working from service

And I edited in that while you were replying, too.

Elmario

Member

Registered: 2023-08-21

Posts: 72

Re: [SOLVED] help with command for disabling dGPU not working from service

He he

Last edited by Elmario (2025-06-01 14:26:49)