Tails

#1 Updated by ioerror 2013-08-14 05:47:35

This bug didn’t seem to affect my machine - though as of 0.20 - my coreboot machine no longer functions after gnome-screensaver blanking without the above xset command.

#2 Updated by ioerror 2013-08-14 05:54:16

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 2013-08-26 10:40:55

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 2013-09-02 11:35:28

xorg.conf ? Some documentation I found so far:

Display Power Management Signaling
https://wiki.archlinux.org/index.php/Display_Power_Management_Signaling

#8 Updated by intrigeri 2013-09-04 03:25:05

Before we start tweaking settings that apparently work well for the rest of us, please test with a build from feature/wheezy, as requested on tails-dev (August 15), and report back. Thanks in advance!

#9 Updated by sajolida 2013-09-05 07:13:11

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 2013-09-06 12:29:24

sajolida wrote:
> Is that any clearer?

Yes, thanks!

So apparently we have two bugs here:

1. Users can’t tweak screen blanking settings using GNOME tools only.
2. 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 2013-09-19 05:05:04

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

#12 Updated by intrigeri 2013-09-19 06:34:54

ThinkPad X32, Tails 0.20.1 with main power connected: screen goes to sleep after about 10 minutes, wakes up after pressing any key.

#13 Updated by sajolida 2013-09-19 07:48:20

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 2013-11-13 09:26:08

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.