Mailinglist Archive: opensuse (1352 mails)

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Re: [opensuse] Black display on media server
On 06/17/2018 07:04 PM, Carlos E. R. wrote:

On Sunday, 2018-06-03 at 15:55 +0200, Carlos E. R. wrote:


I have an sporadic problem with my media server, currently running Leap
42.3. Typically it is running kodi full screen (on XFCE desktop). I
it running on the night (it is also server for other things full time),
so I just power off the display.

Well, sometimes when I power back on the display it remains "dark grey",
ie, black with backlight on; there is some signal, but it is black. No
response to keyboard at all, that I can see. Most times I can not switch
to console text mode. I can do ssh from another machine, tasks are
running. I kill kodi if it still there, kill the screen saver, "chvt 1",
"init 3"... nothing works, the display does not respond. I have no
resource but reboot the server.

On monitors I've had this sort of issue with, there has been a red/green
LED generally close to the power button.  When this LED is green, it
means the computer still has a connection to the monitor.  When the LED
is red, it means that there is no connection between the monitor and the
computer.  Does your monitor have such an LED?  If so, what does it "say"?

I suspect that Kodi has crashed but not fully exited, not restored the
display it grabs (full screen mode).

Happened again and got more info; I was able to recover the display.

kodi chrashed, yes. After sometime, the display wen black. Moving the
mouse it restored. I had other things to do, so I left it be. After a
while it went black, and longer afterwards the display itself powered
off completely. Not "standby", but fully off.

Eventually I used the remote control to power it back on. Black. Moved
mouse, touched keys... no response. I knew the machine was responsive
because I had been doing things on it for hours via ssh. Thinking that
screensaver could be triggered, I carefully typed the password and
enter. No response. Ctrl-alt-f1... no response.

I removed the cable, which is connected to "HDMI1/DVI/PC" and
connected it to HDMI2. No response, the remote control said there was
no signal there. I connected it back to HDMI1, and this time I got
signal: I could see the result of the Ctrl-alt-f1 I did before.
Ctrl-alt-f7 got me back to the normal graphical display. I see my
password typed as a command on the terminal, so the screensaver and
lock was not active.


It is running Leap 42.3 and XFCE.

The display is a Samsung.

In settings, display power management is "off". Screensaver is
disabled. Yet the display itself goes dark and later powers off,
something which kodi impedes when it is running.

I will try enabling power management of the display in XFCE, setting
"switch off" to "never".

Carlos, I'd think you'd want power management to be on; yes, that would
allow the monitor to go black after a specified amount of time, but it
would also allow the monitor to come back on when the computer receives
input from the mouse or keyboard.  IIRC the "specified amount of time"
can be set to forever.

I also noticed in another post you had this:

The current Xorg.0.log says:

[ 39.058] (==) intel(0): DPMS enabled

Despite /etc/X11/xorg.conf.d/50-monitor.conf:

Section "Monitor"
Identifier "DefaultMonitor"
Option "DPMS" "off"

I have this:

# grep DPMS Xorg.0.log
[    39.871] (II) modeset(0): No DPMS capabilities specified
[    40.054] (==) NOUVEAU(G0): DPMS enabled
[    40.118] (==) modeset(0): DPMS enabled

which tells me that the X server gets instructions to change that
setting from its original.  Your logfile could possibly show such changes.

The xset manpage shows several options for setting DPMS for X.

Two other things:

Try hitting Ctrl+Alt+Keypad-Plus and Ctrl+Alt+Keypad-Minus to get the
monitor back from black.  I'm trying to remember from having your same
problems decades ago, but I did find a way to bring an unresponsive
monitor back to life and those two commands force a reread of the
monitor's capabilities, reconnecting to the monitor in the process. 
Those two key commands are explained in the Xorg manpage, if you want
more info on them.

To make it easier to find out what, if anything, crashed, I'd run "ps
-ef --forest > ps.before" when my system is running properly, then the
same command but with output redirected to a different file after the
system horked.  Afterwards I could compare the two files to see what
possibly crashed.  I'd also note if a PID changed; sometimes a server 
(e.g., X) will crash, but then nicely restart without a trace, except it
has a new PID.  Xorg and the stuff around it will be the most relevant.

Hope something here helps.

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