Razer Blade Optimus Backlight Control

From Paul Beesley
Revision as of 10:03, 6 March 2024 by Paulb (talk | contribs) (→‎NVIDIA Driver (Optimus Off))
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If you run Linux on a Razer Blade laptop then you might have difficulty adjusting the brightness on a fresh install. That was the case with my Razer Blade Pro 17 (2021), which is a model with NVIDIA Optimus tech, switching between the integrated Intel HD Graphics and the dedicated RTX 3060.

I found that the brightness function keys worked, the desktop widget showed a change in the value, and so did the values in /sys/class/backlight. The only problem was that nothing actually changed in terms of brightness! I managed to get things working by setting some extra kernel parameters but I didn’t find these in one place so here’s that information collected for you.

These laptops can be set up in two ways by toggling Optimus in the BIOS. Here’s the trick: with Optimus enabled the Intel driver handles brightness control and with Optimus disabled (dedicated GPU only) the NVIDIA driver handles brightness control.

Note: If you have an OLED panel these instructions are unlikely to work for you. OLED panels don’t have a backlight so the method of brightness control is totally different. I don’t have an OLED-equipped laptop to try.

Intel Driver (Optimus On)

With Optimus enabled, the Intel driver will be in control of brightness but you probably need to disable eDP-based brightness control in the Intel open-source driver:

i915.enable_dpcd_backlight=0

For my display - a 2560x1440 165Hz BOE panel - this did the trick. If it doesn't then you might try force enabling this setting instead as I found references to that working for others.

NVIDIA Driver (Optimus Off)

Okay, so the above handles the case where the Intel driver is in control of brightness. What about if you’re using the NVIDIA GPU alone? Recent versions of the proprietary driver (>=460.xx) changed the way that brightness control works and they seem to require a kernel parameter setting:

nvidia.NVreg_RegistryDwords=EnableBrightnessControl=1

If you need help setting kernel parameters then taking a look at the Arch Wiki isn’t a bad place to start: https://wiki.archlinux.org/title/kernel_parameters . The exact method you’ll use depends on your distro and bootloader.

Notes

While researching, I saw a lot of comments and posts relating to setting the acpi_backlight= kernel parameter but after setting up my kernel parameters as described here I didn’t need to use that one. If you’re still having issues and want to experiment then the common values are: none, video, vendor, native.

Do note that kernel parameters are case sensitive when entering them.