could not write to /sys

[mcflash]

Hi,
i wanted to change the power_profile of my graphics card. But i could not write the changes to disk because there is no free space in the /sys folder. Although there are several gigs free on the partition.
It worked some days ago, so i have no clue whats wrong.
I hope you could help me! Thanks in advance.

[Snowhog]

Did you make the changes to the file as "root"? /sys is owned by root.

[mcflash]

Did you make the changes to the file as "root"? /sys is owned by root.

Of course!

[SteveRiley]

/sys is not part of the filesystem in any partition. It's a virtual filesystem created by the kernel that holds information while the system is booted. More information: http://askubuntu.com/questions/34193...rectory-in-sys

Can you post here the exact steps you're trying to complete?

[mcflash]

Sorry, it seems, i have misconfigured something here. In the file /sys/class/drm/card0/device/power_method is dpm set. Can´t change it to 'profile'. Nano says 'invalid argument'. I must have set dpm somewhere permanently. Cause when i change power_dpm_state to 'battery' it works.

[mcflash]

/sys is not part of the filesystem in any partition. It's a virtual filesystem created by the kernel that holds information while the system is booted. More information: http://askubuntu.com/questions/34193...rectory-in-sys

Thanks for this info. Maybe i should have posted my problem to the 'help the new guy' thread :-/ Seems i have still a lot to learn.

[SteveRiley]

Sorry, it seems, i have misconfigured something here. In the file /sys/class/drm/card0/device/power_method is dpm set. Can´t change it to 'profile'. Nano says 'invalid argument'. I must have set dpm somewhere permanently. Cause when i change power_dpm_state to 'battery' it works.

Try this:

echo "profile" | sudo tee /sys/class/drm/card0/device/power_method >/dev/null

Now check the contents of the file. Is it set to profile?

[mcflash]

Try this:

echo "profile" | sudo tee /sys/class/drm/card0/device/power_method >/dev/null

Executing this gives an error message: invalid argument. power_method is still dpm.

But its ok. The card is quite quiet. I just thought it was a bit qieter with power_method = profile and power_profile=low.

And this way it was persistent by setting ati-power-config in /init.d/
When i now set ati-power-profile to "echo balanced > /sys/class.../power_dpm_state" and "echo low > /sys/class/.../power_dpm_force_performance_level" in ati-power-config or rc.local it does not work. Always stays at "balanced" and "auto". Dont know why. Must have misconfigured something.

[SteveRiley]

Hm, "invalid argument" usually means exactly that.

Regarding /etc/rc.local, did you set the execution bits on the file?

[mcflash]

Hm, "invalid argument" usually means exactly that.

Regarding /etc/rc.local, did you set the execution bits on the file?

1. I know. But the options i tried to set are valid. I had this problem when i was fiddling around with the power settings for the graphics card. When power_method was set to dynpm i got the same error message when setting the power_profile to "low". So i think, dpm must be preset somewhere else in the system. When i have some spare time, i will have a look at the kernel and boot options.

2. Yes. I start fancontrol with "service fancontrol start" in the rc.local file.

[SteveRiley]

No, I mean did you set the execution bits so that they look like this:

steve@t520:~$ ll /etc/rc.local
-rwxr-xr-x 1 root root 340 May 31 21:01 /etc/rc.local*

Do it with sudo chmod 755 /etc/rc.local

[mcflash]

No, I mean did you set the execution bits so that they look like this:

steve@t520:~$ ll /etc/rc.local
-rwxr-xr-x 1 root root 340 May 31 21:01 /etc/rc.local*

Permissions are set like you have shown.

[SteveRiley]

Sounds like we've reached the point where perhaps the current driver is expecting different values than what you might be seeing in some documentation or something. Probably more research is in order.