GNOME Bugzilla – Bug 736270
Brightness controls should not be shown in computers without brightness control interfaces
Last modified: 2014-09-08 16:07:10 UTC
Gnome 3 always shows brightness controls in both the top bar and the energy configuration window. These controls are useless in computers without brightness control interfaces, that is, most desktop computers except all-in-one models.
What's the output of: xrandr -q --verbose and: /sys/class/backlight/ on an affected system?
Created attachment 285658 [details] xrandr -q --verbose output
I have attached the output of xrandr -q --verbose in my desktop computer. `ls /sys/class/backlight/` returns one element in my desktop computer: acpi_video0. But as you may already notices, the kernel brightness interface is a bit unreliable, like... my desktop says it has a brightness interface but it doesn't and my laptop says it has no one, neither two, but three brightness interfaces.
There are actually 2 bugs. One that the Intel video driver seems to think it can drive brightness on your screen connected via HDMI. The other is that the kernel thinks it has brightness it can drive when it cannot. Those, I'm afraid, are bugs in the kernel and in the Intel video driver. Please file bugs at http://bugzilla.kernel.org for the kernel (it shouldn't show a backlight interface for your machine). Feel free to copy the URL for the bug here, or CC: me on the bug, so that I can answer to the kernel developers if there are questions related to how GNOME uses the backlight devices.