On my HP6720s laptop, I tend to keep the backlight brightness at a few stops lower than maximum. MPlayer and VLC both cause the brightness to jump to maximum whenever a video is played, and today I traced this problem to their disabling DPMS to avoid the screen blanking through seeming inactivity while watching a movie. The shell command: xset -dpms has the same effect. I've stuck the Ubuntu bug's URL in the URL field, for your convenience. As you'll see, another user has this issue, but on his machine, a Fujitsu Siemens Amilo Pi 2515, the screen brightness jumps to minimum rather than maximum.
On Fri, Mar 28, 2008 at 15:59:53 -0700, bugzilla-daemon@freedesktop.org wrote: > MPlayer and VLC both cause the brightness to jump to maximum whenever a video > is played, and today I traced this problem to their disabling DPMS to avoid the > screen blanking through seeming inactivity while watching a movie. > Please attach your X config and log. Cheers, Julien
Created attachment 15559 [details] Config file
Created attachment 15561 [details] Log file Log and config file attached. The version of Xorg is the version installed at the time of writing by Ubuntu 8.04 alpha.
I've noticed the same thing, running an Asus z35f, kubuntu 8.04, kernel 2.6.24-19-generic. I think I have a suspect: # cd /sys/class/backlight/ :/sys/class/backlight# ls acpi_video0 asus-laptop These two devices have different values for what the "brightness" is currently set to, different values for max brightness, etc. If I now type these two commands, my brightness does not change: /sys/class/backlight# bright=`cat asus-laptop/brightness` /sys/class/backlight# echo $bright > asus-laptop/brightness If I type these two commands, however, the screen brightness changes to the same dim value I get when I type "xset -dpms": /sys/class/backlight# bright=`cat acpi_video0/brightness` /sys/class/backlight# echo $bright > acpi_video0/brightness Worth checking out what's listed in /sys/class/backlight as well as other settings, IMHO... I know technically having two backlight devices is not a problem with freedesktop or xorg, that's a kernel or kernel module issue. However, if X is using /sys/class/backlight/acpi_video0 regardless of what else is there, then... well, wouldn't that be an easy thing to make configurable?
@John: Interesting - but if that's the cause, it doesn't apply on my machine I'm afraid. I've just checked, and in /sys/classes/backlight I only have the one directory - acpi_video0 - and your test case: /sys/class/backlight# bright=`cat acpi_video0/brightness` /sys/class/backlight# echo $bright > acpi_video0/brightness doesn't cause the brightness change on my machine.
May not be the culprit, then. Although, to beat a dead horse, replacing "brightness" with "max_brightness" in my case yields the identical behavior as I keep my monitor on 100%. So, if xset -dpms is invoking something akin to: /sys/class/backlight/acpi_video0# echo `cat max_brightness` > brightness ...then you'd get brightening on your machine, dimming on mine.
Are you still having these issues?
This is an intel ddx issue if it's anything.
Reporter, for this ooollldddd bug still issue? We will close this in a month if not feedback received.
No feedback in many months, closing as resolved works for me. Please re-open is still the case after testing latest https://cgit.freedesktop.org/drm-tip and send dmesg from boot with drm.debug=0x1e log_buf_len=4M?
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