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#1 2012-12-15 17:04:22

koz
Member
Registered: 2012-01-09
Posts: 37

[SOLVED] Backlight on Samsung QX412

Hello,

I am having some issues with the backlight on my machine (Samsung QX412 3.6.10-1 x86_64, KDE).

The only definitive way I can control brightness is echoing into /sys/class/backlight/XXXX.
I have 3 folders here acpi_video0, acpi_video1 and intel_backlight.
I can control brightness through all three of them.

In my attempt to get proper control (though hotkeys and KDE's GUI tool) I added "acpi_osi=Linux acpi_backlight=vendor", this gives me two entries in intel_backlight and samsung.

Now this is where things get interesting. I now have brightness with a twist.
Using KDE's tool, I can bring the brightness down to about 30-40%, moving the slider around the screen flickers a bit and it gets brighter or dimmer by 10%.
I can lower brightness via /sys/class/backlight/samsung/brightness, but I can't bright it back up.

The only way to get it up to a decent level is via /sys/class/backlight/intel_backlight/brightness.
(Though plugging in the power cable, sets brightness to full 100%)

Any ideas on what can be done about this?


Edit:
As per: https://bbs.archlinux.org/viewtopic.php?pid=1211350

Issue has been solved by using "acpi_backlight=vendor" and disabling the "samsung_laptop" module.
Many thanks to nlabrad.

Last edited by koz (2012-12-29 09:16:38)

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