0

I am having an issue on my HP Pavilion g7-1350dx laptop. Whenever I press the keyboard's brightness keys, I notice two things: the display brightens by two steps instead of one, and the Unity OSD displays a shift by two steps. The output of acpi_listen is as follows when I press each button once (first up, then down).

video/brightnessup BRTUP 00000086 00000000
video/brightnessdown BRTDN 00000087 00000000

I have found no solution for this problem to date, however I will mention that this problem is nonexistent when not logged in. When I am idle at lightdm's login screen, pressing either of these buttons only adjusts brightness by one step.

As a side note, I am using fglrx-updates, the proprietary AMD driver for an AMD/ATI BeaverCreek Radeon HD 6520G. I have also looked into the system settings for a shortcut that gnome-settings-daemon uses for brightness, but I could find no such shortcut. I have also tried disabling Action Keys Mode in the BIOS settings, this hasn't worked either.

Any insight or links to answered questions would be greatly appreciated.

Drew Stewart
  • 611
  • Is it okay for you to use other shortcut keys with proper brightness increment? Based on that, I can give you some steps to solve it. – Wolverine Dec 29 '14 at 18:49
  • If by that you mean to set a different set of keys to control brightness, then I'd be perfectly fine with that. I just need a shortcut-based way to control brightness. – Drew Stewart Dec 29 '14 at 18:52
  • Check if the following file exists in the specified directory. /sys/class/backlight/acpi_video0/brightness. – Wolverine Dec 29 '14 at 18:53
  • That file exists, according to the output of find. – Drew Stewart Dec 29 '14 at 18:56
  • Could you say me the content of the file? – Wolverine Dec 29 '14 at 18:57
  • Seems rather empty. 8 is the only text in the file. – Drew Stewart Dec 29 '14 at 18:59
  • Actually, that's the value for the brightness. – Wolverine Dec 29 '14 at 19:00
  • The following site can solve you the issue. http://thanhsiang.org/faqing/node/180. But it doesn't regard shortcut keys for brightness. I'm working on that and will notify once done it. Check out if the brightness changes immediately after the brightness value gets changed using the command given in the site. – Wolverine Dec 29 '14 at 19:07
  • Finally, I found a reference. I'm pretty sure the marked answer in the following link can make your issue solved. http://askubuntu.com/questions/173921/why-does-my-thinkpad-brightness-control-skip-steps. – Wolverine Dec 29 '14 at 19:20
  • That's done the trick. I followed the steps that were non-specific to a Thinkpad and it works fine now. Post that as an answer and I'll accept it. (For a moment I thought I'd have to do a complicated mess involving desktop shortcuts to shell scripts.) – Drew Stewart Dec 29 '14 at 19:27
  • You could create a custom shortcut key on your own. Right? – Wolverine Dec 29 '14 at 19:34
  • As it turns out, I can use the keyboard's default shortcuts by using the method you referenced. After adding echo -n 0 > /sys/module/video/parameters/brightness_switch_enabled to /etc/rc.local, everything works fine. – Drew Stewart Dec 29 '14 at 19:37
  • I'm glad it worked. – Wolverine Dec 29 '14 at 19:39

1 Answers1

1

Changing the brightness value in the /sys/class/backlight/acpi_video0/brightness file can make the issue solved. Here the command:

echo {brightness_value} > /sys/class/backlight/acpi_video0/brightness

Brightness value must be between 0 to 20. I'm not sure whether it can vary device to device.

You could create a script and invoke it on shortcut key press.

I found a reference. I'm pretty sure the marked answer in the following link can make your issue solved. Why does my Thinkpad brightness control skip steps?.

Community
  • 1
Wolverine
  • 654