Description of problem: gnome power manager asks the X server twice per second what the current video mode is to find out if it changed. On a power aware system (tickless idle etc) this is causing the system to eat more power than needed (since this breaks up the cpu sleeps, and causes several context switches as well). The frequency for this polling is clearly much to high, you can hardly even change your physical mode that fast. In addition, X sends apps an event when the mode changes, so there isn't even really a need to poll for this! At minimum I would like to ask the g_timeout_add delay to be increased from 500 to 5000 or so to get rid of the bigger power usage problem, but ideally the entire polling should go away.
> ...but ideally the entire polling should go away. Ohh I agree completely. >In addition, X sends apps an event when the mode changes It does? That part of the code was written by Jon McCann (cc'ing) so I'm not aware of all the funnies. Richard.
To make the polling go away we need to fix the DPMS extension to send events on changes. Until then we need it. The requirements for most user visible effects is a response time of under two seconds. We'd need to carefully look at this. Please file this bug upstream with xorg and gnome-power-manager. Thanks.
Also, please point to code or docs where X sends an event on DPMS changes. Even Keith Packard wasn't aware of this when I asked him at GUADEC. Thanks.
Unfortunately, XDPMS seems event-less: #define DPMSNumberEvents 0
So fix the X screen saver extension to send DPMS related events like it does for other screen saver events. Patches gratefully accepted; X.org 7.2 closes in two weeks.
This is beyond my skills I'm afraid. Could someone with higher code-fu hack x.org a little? Thanks.
I can try to talk ajax into it...
It would be nice to make the DPMS extension send events on its own without having to rely on and add more confusion to the screensaver extension.
Yeah, it's just a DPMS protocol bump, no need to add junk to screensaver. Working on it.
Any news on this guys? Anything I can do to help?
Any news, Adam? If this is making g-p-m use more battery than it saves we should try to get this fixed sooner rather than later.
I'm getting some bad publicity here: http://www.linuxpowertop.org/known.php#xorg Not cool. Ajax, have you got any ideas on how to do this - shall I talk to upstream about if this is a good idea or just send a patch? If any of you guys have any test-patches - can you make sure you attach them here. Thanks.
I believe the solution for this is going to arrive in the form of xrandr obsoleting the dpms extension. xrandr seems to become the new Über-extension.
Based on the date this bug was created, it appears to have been reported against rawhide during the development of a Fedora release that is no longer maintained. In order to refocus our efforts as a project we are flagging all of the open bugs for releases which are no longer maintained. If this bug remains in NEEDINFO thirty (30) days from now, we will automatically close it. If you can reproduce this bug in a maintained Fedora version (7, 8, or rawhide), please change this bug to the respective version and change the status to ASSIGNED. (If you're unable to change the bug's version or status, add a comment to the bug and someone will change it for you.) Thanks for your help, and we apologize again that we haven't handled these issues to this point. The process we're following is outlined here: http://fedoraproject.org/wiki/BugZappers/F9CleanUp We will be following the process here: http://fedoraproject.org/wiki/BugZappers/HouseKeeping to ensure this doesn't happen again.
This bug has been in NEEDINFO for more than 30 days since feedback was first requested. As a result we are closing it. If you can reproduce this bug in the future against a maintained Fedora version please feel free to reopen it against that version. The process we're following is outlined here: http://fedoraproject.org/wiki/BugZappers/F9CleanUp
Changing version to '9' as part of upcoming Fedora 9 GA. More information and reason for this action is here: http://fedoraproject.org/wiki/BugZappers/HouseKeeping
The new IDLETIME sync counter is close enough. We'll get per-output DPMS in RANDR someday too, which will probably get its own events.