Brightness is "not supported" on dell xps 16

[Tournier Mathieu]

system : dell xps 16 with ubuntu 9.04 (64bit)
kernel : 2.6.28-13-generic

I can't change the brightness of my screen whatever the software I use (when I move the brightness bar nothing happens)
Keyboard keys (brightness-down,brightness-up) work
This is what returns the command grep -R . /proc/acpi/video/* :

/proc/acpi/video/M86/DP0/EDID:<not supported>
/proc/acpi/video/M86/DP0/brightness:<not supported>
/proc/acpi/video/M86/DP0/state:state: 0x1f
/proc/acpi/video/M86/DP0/state:query: 0x00
/proc/acpi/video/M86/DP0/info:device_id: 0x0220
/proc/acpi/video/M86/DP0/info:type: UNKNOWN
/proc/acpi/video/M86/DP0/info:known by bios: no
/proc/acpi/video/M86/HDTV/EDID:<not supported>
/proc/acpi/video/M86/HDTV/brightness:<not supported>
/proc/acpi/video/M86/HDTV/state:state: 0x1f
/proc/acpi/video/M86/HDTV/state:query: 0x00
/proc/acpi/video/M86/HDTV/info:device_id: 0x0210
/proc/acpi/video/M86/HDTV/info:type: UNKNOWN
/proc/acpi/video/M86/HDTV/info:known by bios: no
/proc/acpi/video/M86/LCD/EDID:<not supported>
/proc/acpi/video/M86/LCD/brightness:<not supported>
/proc/acpi/video/M86/LCD/state:state: 0x1f
/proc/acpi/video/M86/LCD/state:query: 0x00
/proc/acpi/video/M86/LCD/info:device_id: 0x0110
/proc/acpi/video/M86/LCD/info:type: UNKNOWN
/proc/acpi/video/M86/LCD/info:known by bios: no
/proc/acpi/video/M86/CRT/EDID:<not supported>
/proc/acpi/video/M86/CRT/brightness:<not supported>
/proc/acpi/video/M86/CRT/state:state: 0x1f
/proc/acpi/video/M86/CRT/state:query: 0x00
/proc/acpi/video/M86/CRT/info:device_id: 0x0100
/proc/acpi/video/M86/CRT/info:type: UNKNOWN
/proc/acpi/video/M86/CRT/info:known by bios: no
/proc/acpi/video/M86/DOS:DOS setting: <7>
/proc/acpi/video/M86/POST:<not supported>
/proc/acpi/video/M86/POST_info:<not supported>
/proc/acpi/video/M86/ROM:<TODO>
/proc/acpi/video/M86/info:Switching heads: yes
/proc/acpi/video/M86/info:Video ROM: no
/proc/acpi/video/M86/info:Device to be POSTed on boot: no

[Victor Vargas (kamus)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. Unfortunately, we can't fix it because your description didn't include enough information. We'd be grateful if you would then provide a more complete description of the problem.

We have instructions on debugging some types of problems at http://wiki.ubuntu.com/DebuggingProcedures

Regards

[Tournier Mathieu (mathieutournier)]

This bug has been solve, thank you !
It works now ;-)

[David Tombs (dgtombs)]

I'm closing this report since the issue is no longer reproducible. Thanks, Tournier, for taking the time to make Ubuntu better.

[Boniek (boniek12p)]

This bug report is being closed due to your last comment regarding this being fixed with an update. For future reference you can manage the status of your own bugs by clicking on the current status in the yellow line and then choosing a new status in the revealed drop down box. You can learn more about bug statuses at https://wiki.ubuntu.com/Bugs/Status . Thank you again for taking the time to report this bug and helping to make Ubuntu better. Please submit any future bugs you may find.