The Ubuntu Power Consumption Project

Bug #1245474
Comment #38

Comment 38 for bug 1245474

Revision history for this message

Ted Felix (tedfelix) wrote on 2014-02-04:

#38

Robert Ancell:
> It seems likely the problem is either unity-greeter not configuring / running the correct plugin in g-s-d

It appears that the power plugin is indeed running in both 13.04 and 13.10 as I am seeing logging from it in /var/log/lightdm/x-0-greeter.log in both 13.04 and 13.10.

> or g-s-d being broken.

One key thing that is different between the two logs is that this line appears in 13.10, but not in 13.04:

(gnome-settings-daemon:1507): power-plugin-WARNING **: Failed to run GetActive() function on screensaver: GDBus.Error:org.freedesktop.DBus.Error.UnknownMethod: No such interface 'org.gnome.ScreenSaver' on object at path /org/gnome/ScreenSaver

I do know that the power plugin's dpms feature is driven by org.gnome.screensaver, so since connecting to that is failing in 13.10, that might be related to the issue.

Eugene Crosser:
> my observations show that the problem is not that proper setting are *not applied*, but that they are *overridden* with wrong values afterwards.

This is not what I'm seeing. The DPMS timeouts are not used at the login screen in 13.04 to power off the monitor. The screensaver timeouts are used instead. And the screensaver timeouts are not being modified by anyone when lightdm is running. You can verify this by modifying the display-setup-script and session-setup-script to do an "xset q" before and after the 10 second sleep and log this someplace where it can be easily found. Then examine the screensaver timeouts (not the DPMS) timeouts. The screensaver timeouts stay at 600 for the login screen.

Certainly, the DPMS timeouts can be used as a successful workaround. However, that's not how 13.04 did it. With 13.04, the DPMS timeouts are 0, and the screen still powers off at the login screen.

My plan at this point is to try and run g-s-d in debug mode. I'm not sure how to do that elegantly. I'm going to try pointing /usr/bin/g-s-d to a script that adds on --debug. If anyone has a better suggestion, I'd love to hear it. Once g-s-d is running in debug, I should be able to see it power the monitor on/off in 13.04 and perhaps some additional clues in 13.10. Worst case. I have been doing some power plugin hacking recently, so I can easily drop in a replacement with further logging.

As always, no guarantee this will get me anywhere. I've run into many brick walls trying to figure this out over the past few weeks.

Robert Ancell:
> It seems likely the problem is either unity-greeter not configuring / running the correct plugin in g-s-d

It appears that the power plugin is indeed running in both 13.04 and 13.10 as I am seeing logging from it in /var/log/lightdm/x-0-greeter.log in both 13.04 and 13.10.

> or g-s-d being broken.

One key thing that is different between the two logs is that this line appears in 13.10, but not in 13.04:

I do know that the power plugin's dpms feature is driven by org.gnome.screensaver, so since connecting to that is failing in 13.10, that might be related to the issue.

Eugene Crosser:
> my observations show that the problem is not that proper setting are *not applied*, but that they are *overridden* with wrong values afterwards.

This is not what I'm seeing.  The DPMS timeouts are not used at the login screen in 13.04 to power off the monitor.  The screensaver timeouts are used instead.  And the screensaver timeouts are not being modified by anyone when lightdm is running.  You can verify this by modifying the display-setup-script and session-setup-script to do an "xset q" before and after the 10 second sleep and log this someplace where it can be easily found.  Then examine the screensaver timeouts (not the DPMS) timeouts.  The screensaver timeouts stay at 600 for the login screen.

Certainly, the DPMS timeouts can be used as a successful workaround.  However, that's not how 13.04 did it.  With 13.04, the DPMS timeouts are 0, and the screen still powers off at the login screen.

My plan at this point is to try and run g-s-d in debug mode.  I'm not sure how to do that elegantly.  I'm going to try pointing /usr/bin/g-s-d to a script that adds on --debug.  If anyone has a better suggestion, I'd love to hear it.  Once g-s-d is running in debug, I should be able to see it power the monitor on/off in 13.04 and perhaps some additional clues in 13.10.  Worst case. I have been doing some power plugin hacking recently, so I can easily drop in a replacement with further logging.

As always, no guarantee this will get me anywhere.  I've run into many brick walls trying to figure this out over the past few weeks.