I think I've figured out how to trigger it. The computer in question is a laptop, with an external CRT connected via a docking station some of the time -- and all the times the DPMS Off: value has been incorrectly set, the laptop has been docked with the CRT connected.
In order to trigger it I seem to need to: - boot up docked, with the CRT on - suspend to RAM - turn off the CRT - unsuspend (which is hit the power button in the case of this laptop) - while unsuspending, turn on the CRT (at the "right" time) In that situation I get: DPMS (Energy Star): Standby: 0 Suspend: 0 Off: 60 DPMS is Enabled Monitor is On or: DPMS (Energy Star): Standby: 0 Suspend: 0 Off: 300 DPMS is Enabled Monitor is On with the "Off:" time being set to the difference between the Power Mangement time and the Screensaver time. And if that time is non-zero, then playing with the adjusters seems to set the Off: time to the difference between the two (which definitely seems to be the wrong behaviour to me). So there appears to be two things going on: - there's something in Gnome (presumably Power Management) which is incorrectly setting the DPMS Off time to the difference between the Power Management off time and the Screensaver time (possibly when it notices a non-zero Off: time -- but irrespective, it's still doing the wrong thing: if it's going to set it, it should be to the total Power Management off time, or 0) - there's a race condition between the CRT waking up and the DPMS being reset to zero (possibly by some other power management program or task), where the DPMS setting doesn't "stick" until the CRT is ready to accept it (for which the fix is presumably to have the power management reapply the setting a little while, eg, 30 seconds, after either (a) unsuspend, or (b) the arrival of a new monitor. It appears once it becomes a non-zero value it's difficult to get the "reset to 0" behaviour back; I did manage it with one suspend (powering on the CRT a little earlier in the unsuspend), but other attempts still didn't reset it to zero (including ensuring the CRT was fully powered on before unsuspending). In case it matters, the laptop is a HP NC6220, which has Intel integrated graphics (Intel 915GM), with a HP docking station, and a Viewsonic E70 CRT connected to it. Anyway it seems to me that if the Gnome power manager is going to manage the display power off itself, it should probably be explicitly resetting the X DPMS Off: time (and others) to 0, and definitely never setting it to the difference between the screensaver time and the Power Management screen off time. That seems to be the core bug. Ewen -- [Gutsy] Display sleep sets wrong DPMS off time https://bugs.launchpad.net/bugs/190537 You received this bug notification because you are a member of Ubuntu Bugs, which is the bug contact for Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
