Re: [gpm] Brightness Applet - "Cannot get laptop panel brightness"

[Richard Hughes <hughsient gmail com>]

On Sat, 2007-04-28 at 15:42 -0700, Paul M Edwards wrote:
> The message "Cannot get laptop panel brightness" is displayed as the
> applet's hover message on my Fujitsu P1510D tablet running Ubuntu
> 7.04.

Sure, sounds like it's not recognised by HAL

> Brightness can be adjusted on this machine manually using a line
> similar to this:
> root MiniMe:~# echo 3 > /proc/acpi/video/GFX0/LCD/brightness
> 
> With 1 through 8 valid possible values.

So it's not expressed in /sys/class/backlight?

> I've tried sending a message directly to hal as indicated on the
> website, but an error is recieved:
> root MiniMe:~# dbus-send --system --print-reply --dest=org.freedesktop.Hal \
> > /org/freedesktop/Hal/devices/acpi_lcd \
> > org.freedesktop.Hal.Device.LaptopPanel.SetBrightness \
> > int32:2
> Error org.freedesktop.DBus.Error.UnknownMethod: Method "SetBrightness"
> with signature "i" on interface
> "org.freedesktop.Hal.Device.LaptopPanel" doesn't exist

No, it sounds like HAL doesn't know about your panel. I did write a HAL
patch once to get and set using /proc/acpi/video but it was rejected as
we couldn't usually find the right device, or know the correct number of
steps.

> So, my question is... Where should I file bugs?
> - HAL
> - gnome-power-manager general
> - the brightness applet
> - all of the above?

Well, HAL if you are impatient; IIRC Luming Lu was converting the ACPI
brightness control to sysfs backlight class - when this is done it
should "just work" with HAL, g-p-m, and the brightness applet.

See http://lkml.org/lkml/2006/11/10/221 for the initial patch - but I'm
not sure of the status in mainline.

> Thanks in general for gnome-power-manager; it's good stuff.

Thanks!

Richard.