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Bug 736270 - Brightness controls should not be shown in computers without brightness control interfaces
Brightness controls should not be shown in computers without brightness contr...
Status: RESOLVED NOTGNOME
Product: gnome-settings-daemon
Classification: Core
Component: power
3.12.x
Other Linux
: Normal normal
: ---
Assigned To: gnome-settings-daemon-maint
gnome-settings-daemon-maint
Depends on:
Blocks:
 
 
Reported: 2014-09-08 15:45 UTC by Alicia Boya García
Modified: 2014-09-08 16:07 UTC
See Also:
GNOME target: ---
GNOME version: ---

Attachments
xrandr -q --verbose output (11.17 KB, text/plain)
2014-09-08 15:56 UTC, Alicia Boya García 		Details

Description Alicia Boya García 2014-09-08 15:45:41 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.
Comment 1 Bastien Nocera 2014-09-08 15:49:54 UTC 
What's the output of:
xrandr -q --verbose
and:
/sys/class/backlight/

on an affected system?
Comment 2 Alicia Boya García 2014-09-08 15:56:30 UTC 
Created attachment 285658 [details]
xrandr -q --verbose output
Comment 3 Alicia Boya García 2014-09-08 15:56:46 UTC 
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.
Comment 4 Bastien Nocera 2014-09-08 16:07:10 UTC 
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.