http://bugzilla.kernel.org/show_bug.cgi?id=12249
--- Comment #108 from Peter Klotz <peter.kl...@aon.at> 2009-04-07 19:55:23 ---
>From a kernel point of view this may be true. However Gnome shows quite erratic
behavior.
"echo 10 > /proc/acpi/video/VGA/LCD/brightness" no longer shows an error
message which is definitely better than before.
Iterating through all values in /proc/acpi/video/VGA/LCD/brightness works
perfectly and changes the brightness as expected (10=lowest, 100=highest).
This scenario however shows odd behavior:
* Set maximum brightness: echo 100 > /proc/acpi/video/VGA/LCD/brightness
* r...@asus:/proc/acpi/video/VGA/LCDD# cat brightness
levels: 10 16 21 27 33 39 45 51 57 63 69 74 81 87 93 100
current: 100
* r...@asus:/proc/acpi/video/VGA/LCDD# grep . /sys/class/backlight/*/*
/sys/class/backlight/acpi_video0/actual_brightness:0
/sys/class/backlight/acpi_video0/bl_power:0
/sys/class/backlight/acpi_video0/brightness:15
/sys/class/backlight/acpi_video0/max_brightness:15
* Reducing the brightness level by one using the corresponding brightness key
* The brightness stays very high (I would assume 93)
* r...@asus:/proc/acpi/video/VGA/LCDD# cat brightness
levels: 10 16 21 27 33 39 45 51 57 63 69 74 81 87 93 100
current: 16
* r...@asus:/proc/acpi/video/VGA/LCDD# grep . /sys/class/backlight/*/*
/sys/class/backlight/acpi_video0/actual_brightness:1
/sys/class/backlight/acpi_video0/bl_power:0
/sys/class/backlight/acpi_video0/brightness:14
/sys/class/backlight/acpi_video0/max_brightness:15
* Pressing the brightness key a few more times does not change anything, but
then abruptly minimum brightness is set
* r...@asus:/proc/acpi/video/VGA/LCDD# cat brightness
levels: 10 16 21 27 33 39 45 51 57 63 69 74 81 87 93 100
current: 10
* r...@asus:/proc/acpi/video/VGA/LCDD# grep . /sys/class/backlight/*/*
/sys/class/backlight/acpi_video0/actual_brightness:15
/sys/class/backlight/acpi_video0/bl_power:0
/sys/class/backlight/acpi_video0/brightness:0
/sys/class/backlight/acpi_video0/max_brightness:15
Do these values look sane to you?
It seems strange that manually executing "echo 16 >
/proc/acpi/video/VGA/LCD/brightness" results in a dark screen whereas setting
brightness with Gnome results in a very bright screen.
In both cases /proc/acpi/video/VGA/LCD/brightness contains "current: 16".
Is /proc/acpi/video/VGA/LCD/brightness a reliable source for the current
brightness value or should /sys/class/backlight/acpi_video0/brightness be used
instead?
--
Configure bugmail: http://bugzilla.kernel.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are on the CC list for the bug.
------------------------------------------------------------------------------
This SF.net email is sponsored by:
High Quality Requirements in a Collaborative Environment.
Download a free trial of Rational Requirements Composer Now!
http://p.sf.net/sfu/www-ibm-com
_______________________________________________
acpi-bugzilla mailing list
acpi-bugzilla@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/acpi-bugzilla
