xset fails to turn off LCD screen

[Justin Dugger]

Binary package hint: gnome-power-manager

Gnome power manager will turn the screen black but fails to turn the backlight off on my laptop LCD. I suspect a bug in xset causing gnome-power-manager to fail.

Example:
'xset dpms force off'
exhibits the same broken functionality (black screen instead of setting the lower power state of having the backlight off)

In contrast,
'vbetool dpms off'
works as intended.

[Duncan Lithgow (duncan-lithgow)]

On my gutsy running HP dv8220ea laptop the first command looks like it's cutting power to the laptop, but I'm just assuming I can see the difference. The second command gives me the error: "Failed to initialise LRMI (Linux Real-Mode Interface)" I haven't tried as root as I don't understand the command.

[Justin Dugger (jldugger)]

 I should note this bug was filed on a Toshiba Tecra M7. Duncan's comment suggests this might be model specific =(

[Ashley Hooper (ash-hooper)]

Same problem on Toshiba Portege 3480CT. The last version I remember the backlight being able to turn off with xscreensaver and xset was Edgy.

[Martin (martin-wetterstedt)]

I've got a Fujitsu Siemens C1410 with intel graphics, and I've set the power-manager to turn the screen off after 6 minutes. Sometimes the screen turns black (backlight still on) and sometimes the screen doesn't even turn black. This started when upgrading to Gutsy. On my other computer (VIA EPIA) the problem that the power-manager doesn't always shut down the screen also exists.

[Basilio Kublik (sourcercito)]

Hi There
Thank you for taking the time to report this bug and helping to make Ubuntu better. You reported this bug a while ago and there hasn't been any activity in it recently. We were wondering is this still an issue for you?, Can you please try with the live environment of the Desktop CD of the development release - Hardy Heron?

Thanks in advance.

[Justin Dugger (jldugger)]

Is the liveCD nessecary, or can I use my installed Hardy partitions?

[Bryce Harrington (bryce)]

No, liveCD was probably suggested just for convenience if you did not have Hardy installed - testing your installed Hardy partition would be sufficient.

I don't know how to solve this problem, however my one observation would be that this is likely an ACPI issue rather than something specific to gnome-power-manager, so this bug may be mis-filed. If the issue manifests *only* when X is running, it might also be an issue with your X driver.

[Ashley Hooper (ash-hooper)]

I'm running Hardy with latest updates and this still doesn't work for me either.

I don't use gnome-power-manager (just xscreensaver's power management), but even running 'xset dpms force off' doesn't switch off the backlight.

My X driver is 'savage'.

[Basilio Kublik (sourcercito)]

Hi there
As Bryce point out, i ask to test in the live cd, just for your convenience, but a installed hardy is a better test environment for this. I cant reproduce this though, both gnome-power-manager or xset works fine turning off the backlight of my laptop, may it be a driver issue rather than gnome-power-manager?, at this point i don't really know, but i guess is a possibility, anyway, you can take a look at https://wiki.ubuntu.com/DebuggingGNOMEPowerManager to see what information could be of help and how to obtain it so you can include it on this report as separated attachments.

Thanks again for your feedback.

[Ashley Hooper (ash-hooper)]

The problem is most definitely at either the ACPI level, or the X server / driver level. As I mentioned, I don't use G-P-M and I've had this problem ever since Feisty.

[Ashley Hooper (ash-hooper)]

Should I log another bug for this against xserver-xorg-video-savage ?

[Justin Dugger (jldugger)]

I can't duplicate this anymore in hardy. Marking as fixed.