GNOME Bugzilla – Bug 529769
gpm does not dim backlight on Q45
Last modified: 2009-03-04 14:59:36 UTC
Please describe the problem: GPM apparently does not know how to dim the backlight of my Samsung Q45 laptop. [gpm_backlight_brightness_evaluate_and_set] gpm-backlight.c:365 (20:25:20): no dimming hardware [gpm_backlight_sync_policy] gpm-backlight.c:161 (20:25:20): choosing sensible default [gpm_backlight_sync_policy] gpm-backlight.c:163 (20:25:20): laptop, so use GPM_DPMS_METHOD_OFF [gpm_backlight_sync_policy] gpm-backlight.c:195 (20:25:20): BACKLIGHT parameters 0 0 1800, method '4' This leads to the problems that when going to battery the screen is not dimmed and when the idle timeout kicks in the screen is blanked, but the backlight stays on! The xbacklight tool works just fine with this laptop. I'll attach dmesg and debug output from GPM. Steps to reproduce: Actual results: Expected results: Does this happen every time? Other information:
Created attachment 109848 [details] dmesg output
Created attachment 109849 [details] GPM debug output (starting GPM and then unplugging the power supply)
If you try gnome-power-manager from trunk, I recently added XBACKLIGHT support there. Can you confirm trunk works pls?
It seems that it correctly uses XBACKLIGHT, but it still does not dim the screen when going to battery power. I'll attach the log. Maybe I did not install it correctly. Basically I checked it out of SVN and then did: sh autogen sh make sudo make install killall gnome-power-manager /usr/local/bin/gnome-power-manager --verbose --no-daemon 2>&1 | tee gpm-trunk.log Is that sufficient?
Created attachment 109891 [details] GPM trunk debug output (starting GPM and then unplugging the power supply)
BTW, can you confirm that for the original code to work, I need the ACPI video driver (video.ko)? Because that is broken on my laptop (causes a lockup) and thus blacklisted. It would be important to know whether this is the root cause, because hal must also regulate the backlight (which also does not work) and I think it cannot use XBLACKLIGHT because it should work even if X is not running...
Thanks for taking the time to report this bug. However, you are using a version that is too old and not supported anymore. GNOME developers are no longer working on that version, so unfortunately there will not be any bug fixes for the version that you use. By upgrading to a newer version of GNOME you could receive bug fixes and new functionality. You may need to upgrade your Linux distribution to obtain a newer version of GNOME. Please feel free to reopen this bug if the problem still occurs with a newer version of GNOME.