screen turns black after 10 minutes regarless of screensaver settings
The default screensaver waiting time in Tails is set to 30 minutes, nonetheless the screen turns black after 10 minutes at most.
xset -dpms s off fixes this behavior. We should fix that in the ISO somewhere...
#2 Updated by ioerror over 6 years ago
For those wondering about how the X server does screen blanking, I've found this website handy for a primer: http://www.shallowsky.com/linux/x-screen-blanking.html
#6 Updated by ioerror over 6 years ago
I've tried this on Tails systems with extra packages as well as on tails systems with nothing, not even persistence enabled. This bug appears to impact many thinkpad users. I'm not clear if it impacts all users of Tails if the other developers aren't experiencing this issue.
I can confirm that users without any screen saver installed also experience this screen blanking issue. Essentially, to fix it, each user must type the following command at boot:
xset -dpms s off
If that command is typed, it ensures that the screen back light will not turn off after ~10 minutes and if the lid is closed, the LCD back light will turn off but when opened, the screen LCD will turn on again.
We should run that command at boot. What is the best place to hook such a change for the next release?
#7 Updated by akuckartz over 6 years ago
xorg.conf ? Some documentation I found so far:
Display Power Management Signaling
#9 Updated by sajolida over 6 years ago
To answer intrigeri's question: yes, there is no screensaver installed so we were using the wrong terminology. But if you do System → Preferences → Power Management Preferences. The setting for "Put display to sleep when inactive for" is set to "30 minutes". That's what we are talking about.
If I remember correctly, this setting does put the screen to sleep, turns it black. But this behavior is taken over by the DPMS stuff that turns the screen black after only 10 minutes, and not 30. So, for example, if you want to disable this feature and set that preference to "Never", the screen will still turn black after 10 minutes.
If I understand correctly, ioerror is reporting that this DPMS sleep is breaking badly on some computers. So that initial problem, DPMS taking over the configured sleeping delay, is actually more problematic now that it used to be. Even thought the problem has been known for a while.
Is that any clearer?
#10 Updated by intrigeri over 6 years ago
Is that any clearer?
So apparently we have two bugs here:
- Users can't tweak screen blanking settings using GNOME tools only.
- DPMS sleep makes at least one system (a coreboot machine) unusable.
The first bug is a minor one, that indeed has been known for a while (I forgot). Patches are welcome, no emergency, especially if it can't be reproduced on Tails/Wheezy.
Things might be different for the second bug, and we need to assert how broadly it impacts hardware, to start with:
- What hardware can it be reproduced on with Tails 0.20?
- What hardware can it be reproduced on with Tails/Wheezy snapshots?
(It's unclear to me which one "This bug" relates to in "This bug appears to impact many thinkpad users". ioerror?)
Anyone interested in working on this, perhaps it's time to split this ticket in two, then.
#11 Updated by sajolida about 6 years ago
I did some more testing with Tails 0.20.1 on various laptops. The screen turns black after 10 minutes with DPMS, but pressing any key brings them back as usual:
- Thinkpad X61 running on power adapter
- Thinkpad X61 running on battery
- Thinkpad X60s running on power adapter
- Thinkpad X60s running on battery
#13 Updated by sajolida about 6 years ago
lspci reports the same graphical hardware for both Thinkpad X60 (affected for ioerror) and Thinkpad X60s (unaffected for me):
00:00.0 Host bridge: Intel Corporation Mobile 945GM/PM/GMS, 943/940GML and 945GT Express Memory Controller Hub (rev 03)
00:02.0 VGA compatible controller: Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller (rev 03)
00:02.1 Display controller: Intel Corporation Mobile 945GM/GMS/GME, 943/940GML Express Integrated Graphics Controller (rev 03)
#14 Updated by intrigeri about 6 years ago
The "screen goes black after 10 minutes, regardless of GNOME power management settings" issue was reproduced on Tails/Wheezy at commit 7ee3fa8.
Next step: reproduce on current Debian unstable, or Fedora Rawhide, or whatever is close to the latest upstream stuff.
Worst case, we'll workaround this with a
xorg.conf.d snippet or a xsession init script that runs xset, but first we should ensure that this bug is reported to GNOME upstream.