[kde-linux] resume from suspend still leaves video dark

Richard Pickett Richard.Pickett at CSRTechnologies.com
Sat Jul 16 09:11:16 UTC 2005

Well I've got it only happening now when I Fn-Suspend to suspend the
machine, then turn it back on (which unsuspends).

So I tried your experiments with suspending, not taking it off AC.

It may still be a hardware issue, so don't rule that out just yet.  For
example, I don't believe I have *any* settings for configuring screen
brightness, and my hardware remembers the "plugged in" brightness and
"unplugged" brightness settings.

First, let's see if we can rule out KDE.  I presume that you know how to
control your init scripts.  The commands I'll use work on gentoo, so you
may have to modify them to match your setup.

1. If you have XDM/KDM running, log out and turn it off and get a fresh
start.  ('telinit 3' & 4, '/etc/init.d/xdm stop')

2. As root, check your logs.  '# tail -n 40 /var/log/everything/current'

3. As either root or user (on another virtual console), start a raw X
session:  '$ X 2>&1 | tee x-log.txt'

4. You should have a nice, bright screen.  Unplug power.  Observe.  Plug
power back in.  Observe.

Instead of unplug I suspend, close, re-open (which reactivates it). Upon
reactivation it is dimmed.  I can stop X and restart X again and it's
back to bright. So I don't think it's the hardware at all. As matter of
fact, as soon as X exits and it goes back to text it's bright again....

If it did, check the file x-log.txt and /var/log/everything/current for

If you rule out KDE, you may want to post to a Slack list.  -- more
to get a solution there.

OK, checked the x-log.txt. Nothing. Check the /var/log/XFree86.0.log and
do a diff between a time I suspend and a time I don't, the following
lines are in the suspended that aren't in the non-suspended run:

(II) PM Event received: User system Suspend Request
(II) PM Event received: Normal Resume System
(II) Mouse1: ps2EnabledDataReporting: succeeded

So I see that X does get the suspend.

I check all the other logs but don't see anything other than the kernel
picking up on the suspend and resume, but nothing indicating dimming the

Again, it's not really a lighting dimm, it's like all the colors get
converted to darker to consume less energy by having a darker screen
without really changing the light.

Imagine taking an older laptop out into direct sunlight and trying to
read the screen. That's about the same effect (hey, maybe when I restore
from suspend it magically brightens all the surrounding lights...)

And since I can switch to other terminals and they are just as bright as
always, I'm sure this is an X thing.

Here's an even nicer one. I can ALT-CTRL-F1 from X over to console 1,
then switch back and presto, it's dimmed down.

Nice eh?


Did some digging on xfree86.org. got mislead into the dpm stuff (xset
... dpm suspend, etc.)

Stumbled across this page:


(search on the word suspend)

turns out some displays have problems restoring because bios doesn't
understand the video options if they aren't 100% compatible with that
monitor. So I put default depth from 24 *down* to 16 (32 didn't help).
Run just X, switch consoles and back... presto works fine. telinit 4,
bingo works fine. suspend restore, again works as should.

*and* now I also notice that ugly color pixilation on the kde background
image fading is now gone and a smooth image is there.

So even though X thought the video could handle 24 bit colors, it could
only do 16.

Now it works great and I'm happy all over again.

Thanks for your suggestions and help.

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