Backlight control with Pascal-based GPUs not working

Graphics / Linux Linux
1

Hi,

I’ve been trying to change the internal backlight on a Clevo notebook with an nVidia GTX 1070 graphics card, hooked up directly to an AU Optronics 120 HZ GSync-capable panel.

So far, nothing worked.

I have tried multiple kernel versions and base systems, ranging from Ubuntu with a 4.4-based Linux kernel to a vendor-specific 4.9-based kernel and my own custom 4.10.2 kernel. Some driver versions tried were 375.26 (on Ubuntu 16.10 with a 4.9-based kernel) and 378.13 (on Ubuntu 16.10 with the stock kernel and a Gentoo system with my self-configured 4.10.2 kernel.) None have working backlight control.

In this message, a likely explanation for the trouble was given:

Given that this issue was confirmed on Feb 2nd 2017, what is the status on this? Has it been fixed with the 378.13 release on Feb 14th 2017? Even with this driver version, I am not able to successfully change the brightness, no matter what I do.

Further, I have found no information on whether the nVidia driver is supposed to create a sysfs node for backlight control or not. Booting up the system with kernel parameter “acpi_backlight=vendor” removes the (so far useless, because any changes to that have no real effect) acpi_backlight0/acpi_video0 backlight sysfs node, but the nVidia driver seems not to create its own.

Help is highly appreciated!

2

Backlight control finally works with the new beta driver version 381.09. Thank you very much for the fix!

3

@Station_ Did you have to set any kernel parameters to get it working? I have tried without any acpi_backlight setting as well as acpi_backlight=vendor and have had no luck.

4

@Station_ I got it working. Apparently hitting the sleep button must have reset something and now it works