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lordblack

Member

Registered: 2014-01-29

Posts: 2

[SOLVED] HP Pavilion dm1: screen brightness issues

Hi I've just updated a laptop I haven't used in 2-3 months, and can no longer change the screen brightness. I've got the Radeon HD 6320 with open source ati drivers, and /sys/class/backlight/radeon_bl0/brightness exists and can be written to (as root) to change the backlight. This is kinda pain in everyday use, but xbacklight just returns

No outputs have backlight property

so it's my only option. I've followed a lot of tips on this problem: loading radeon in initram, adding "acpi_osi=linux acpi_backlight=vendor" to grub etc., but none of them seem to fix it. Is there anyway of writing to /sys/class/.../brightness as non-root or fixing the xbacklight issue?

TIA

Last edited by lordblack (2014-01-29 23:46:00)

Raynman

Member

Registered: 2011-10-22

Posts: 1,539

Re: [SOLVED] HP Pavilion dm1: screen brightness issues

radeon driver doesn't support backlight property and probably never will. I don't know about catalyst. I have a similar laptop (but the radeon_* entry is not really usable) and I use a file in /etc/tmpfiles.d with the following line to make it writable for group "users" during boot:

m /sys/class/backlight/acpi_video0/brightness 0664 root users - -

You could alternatively configure sudo so you can

echo 6 | sudo tee /sys/class/backlight/acpi_video0/brightness

without a password.

lordblack

Member

Registered: 2014-01-29

Posts: 2

Re: [SOLVED] HP Pavilion dm1: screen brightness issues

radeon driver doesn't support backlight property and probably never will.

Damn that's insane, I had no idea. Yeah I'd rather not use catalyst, probably even worse. Thanks for the suggestions though, probably just bind my function keys to a script. Thanks