Screen backlight doesn't shut down

[guigz]

My machine is an Imac G4 800MHz,256Mo Ram,17" LCD screen and Nvidia Geforce 4 video card.
System is Xubuntu Feisty with all the latest updates.I didn't recompile the kernel.
I use the nv drivers since the proprietary drivers are not available for ppc computers.

Everything is working nice except one thing,when I ask the Screen to shut off using DPMS
(xset dpms force off),the screen is getting blank as well,but the backlight is not shut off.
I tried to switch the DPMS thing in xorg.conf without success.

[Olivier Cortès (olive)]

This happens the same here on an Imac G4 800Mhz / 256Mib / 17' LCD / nVIDIA GeForce 4MX.
"xset dpms force off" make the screen go blank but not power off.
System is an up-to-date feisty (with GNOME), but it comes from a dapper, upgraded to edgy, then to feisty. Under Dapper, i manually tuned xorg.conf to add 1440x900 mode, but this is the only system modification I can remember I done on this machine.
dmesg, xorg.conf, Xorg.0.log can be found at http://deep-ocean.net/files/imac/

[Sitsofe Wheeler (sitsofe)]

(This sounds similar to Bug #37540 )

[Adam Niedling (krychek)]

Feisty is not supported anymore. Please reopen if this is still an issue in a later version of Ubuntu.

[Thomas Champagne (lafeuil)]

Hi Adam and others
I think I have the same problem but not the same hardware.
My laptop is an Ibook G4 (powerpc). You can see the output of `lspci -vvnn` here : http://launchpadlibrarian.net/18641260/lspcivvnn.txt

My display doesn't support DPMS. You can see that in the xorg.0.log with the line :
"No DPMS capabilities specified; RGB/Color Display"
Check if you have this line in your xorg.0.log

The only way to put the display in sleep mode is to change the level brightness to 0. I think the GPM (gnome-power-manager) must do that but for the moment it doesn't do it. I created a bug report about this : http://bugzilla.gnome.org/show_bug.cgi?id=550524

Tell me if your problem is the same.
Regards
Thomas

[Adam Niedling (krychek)]

If your display doesn't support DPMS then should Ubuntu be able to put it in sleep mode? Please specify which version of Ubuntu you are using now.

[Thomas Champagne (lafeuil)]

For the moment, Ubuntu run the pbbuttonsd (http://pbbuttons.berlios.de/) daemon to switch off the backlight of my display. But this daemon have the same features than GPM. But GPM have a bug when the display doesn't support DPMS.

I watched in the source code of pbbuttonsd daemon and the program changes the level brightness to 0 for put the display in sleep mode . It's for that I created a bug report for GPM.

Currently, I use Intrepid.

[Charlie Kravetz (cjkgeek)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This bug did not have a package associated with it, which is important for ensuring that it gets looked at by the proper developers. You can learn more about finding the right package at https://wiki.ubuntu.com/Bugs/FindRightPackage . I have classified this bug as a bug in Gnome-Power-Manager.
For future reference you might be interested to know that a lot of applications have bug reporting functionality built in to them. This can be accessed via the Report a Problem option in the Help menu for the application with which you are having an issue. You can learn more about this feature at https://wiki.ubuntu.com/ReportingBugs.

[Charlie Kravetz (cjkgeek)]

Thank you for your bug report. This bug has been reported to the developers of the software. You can track it and make comments here: http://bugzilla.gnome.org/show_bug.cgi?id=550524