LinuxQuestions.org - External Monitor enters Power Save

- Linux - Hardware (https://www.linuxquestions.org/questions/linux-hardware-18/)

- - External Monitor enters Power Save (https://www.linuxquestions.org/questions/linux-hardware-18/external-monitor-enters-power-save-4175665399/)

External Monitor enters Power Save

I am running openSUSE Leap 15.1 on my Lenovo ThinkPad T440p laptop and use the Dell 24' monitor E248WFP as an external second display.
At times the external display goes blank and shows "Entering Power Save".
The laptop display is not effected.
I still could not pinpoint what triggers this behaviour.
It try the usual things "restart", "shutdown", "disconnecting the monitor"
and after a while, sometimes hours, the screen comes to live again.
I checked dmesg, but was not sure what to look for.
I also saved /etc/interrupts and compared it to the file after the display
went blank with the result:

* there was an IO-APIC 9-fastevi interrupt
* there were 2333 new interrupts listed in the line with PCI-MSI
* there were 10449 new interrupts in the line TLB shootdown

I do not want to put anybody on a possible false track, I am just telling
what I have done so far.

I would appreciate any help
* in finding out what goes wrong
* and come up with a solution for avoiding this inconvenience or
at least recover faster from it.

Which DE do you use?

Does executing xrandr wake up the external screen?

Please provide output from inxi -GxxSza (you may need to install if first). It should resemble this if using the openSUSE version:

Code:

> /usr/bin/inxi -GxxSza

System:    Host: gx780 Kernel: 4.12.14-lp151.28.32-default x86_64 bits: 64 gcc: 7.4.1

          Desktop: KDE Plasma 3 dm: N/A Distro: openSUSE Leap 15.1

Graphics:  Card: Intel 4 Series Integrated Graphics Controller bus-ID: 00:02.0 chip-ID: 8086:2e12

          Display Server: X.Org 1.20.3 drivers: modesetting (unloaded: fbdev,vesa)

          Resolution: 1920x1200@59.95hz

          OpenGL: renderer: Mesa DRI Intel Q45/Q43 version: 2.1 Mesa 18.3.2 Direct Render: Yes

or this if using the radically newer current inxi version from upstream web site:

Code:

> inxi -GxxSza

System:    Host: gx780 Kernel: 4.12.14-lp151.28.32-default x86_64 bits: 64 compiler: gcc v: 7.4.1

          parameters: root=/dev/sda13 noresume consoleblank=0 mitigations=auto

          Desktop: KDE 3 wm: kwin dm: N/A Distro: openSUSE Leap 15.1

Graphics:  Device-1: Intel 4 Series Integrated Graphics vendor: Dell driver: i915 v: kernel bus ID: 00:02.0 chip ID: 8086:2e12

          Display: server: X.Org 1.20.3 driver: modesetting unloaded: fbdev,vesa alternate: intel resolution: 1920x1200~60Hz

          OpenGL: renderer: Mesa DRI Intel Q45/Q43 v: 2.1 Mesa 18.3.2 direct render: Yes

Have you checked the monitor's own menu? It's a long shot, but it may have some built-in power-saver setting.

Quote:

Originally Posted by frankbell (Post 6064769)

Have you checked the monitor's own menu? It's a long shot, but it may have some built-in power-saver setting.

+1 to this thought...may not be the OS at all.

External Monitor enters Power Save

This is my reply to mrmazda

Unfortunately, xrandr did not help.
Also xrandr --display HDMI-1
produced

Code:

Can't open display HDMI-1

I installed inxi.
It was a bit tricky to find out that I had to install
in addition also Mesa-demo-x
Entering the command inxi -GxxSza yields:

Code:

inxi -GxxSza

/usr/bin/inxi: illegal option -- a

Dropping option "a" gives

Code:

System:    Host: linux-8r1d Kernel: 4.12.14-lp151.28.32-default x86_64 bits: 64 gcc: 7.4.1

          Desktop: KDE Plasma 5.12.8 (Qt 5.9.7) dm: sddm,sddm Distro: openSUSE Leap 15.1

Graphics:  Card: Intel 4th Gen Core Processor Integrated Graphics Controller bus-ID: 00:02.0 chip-ID: 8086:0416

          Display Server: x11 (X.Org 1.20.3 ) drivers: modesetting (unloaded: fbdev,vesa)

          Resolution: 1366x768@59.99hz

          OpenGL: renderer: Mesa DRI Intel Haswell Mobile

          version: 4.5 Mesa 18.3.2 (compat-v: 3.0) Direct Render: Yes

I hope that helps.

Quote:

Originally Posted by pschmitt (Post 6065100)

Also xrandr --display HDMI-1
produced

Code:

Can't open display HDMI-1

Simply running xrandr will report the names of the connected outputs and the screen ID. --display takes the screen ID. --output takes a connector name.

Quote:

I installed inxi.
It was a bit tricky to find out that I had to install
in addition also Mesa-demo-x
Entering the command inxi -GxxSza yields:

Code:

inxi -GxxSza

/usr/bin/inxi: illegal option -- a

That's a result of using the antique inxi rpm from 15.1, and why I provided the URL to the current version. If you consult its man page you'll see it has an updates switch -U. It should also explain how to make it work.

Quote:

Dropping option "a" gives

Code:

System:    Host: linux-8r1d Kernel: 4.12.14-lp151.28.32-default x86_64 bits: 64 gcc: 7.4.1

          Desktop: KDE Plasma 5.12.8 (Qt 5.9.7) dm: sddm,sddm Distro: openSUSE Leap 15.1

a produces the line that's missing from the antique.

man xrandr might have something to apply to the external output to wake it back up, maybe --auto. How to keep it active is another question. https://www.kernel.org/doc/Documenta...parameters.txt has some cmdline options that can affect video behavior, e.g. acpi_backlight= or consoleblank=.

External Monitor enters Power Save

answer to frankbell and scase

good point!
What I did not mention in my first post: I had connected the Dell monitor
to a second laptop running kubuntu as OS and everything work without a hitch.
But, since I still do not know what triggers the entering into power save this was not
finally conclusive. Maybe, if I had worked with that laptop a little long the effect
might have happened.
So, I checked today the OSD menue of the Dell monitor. It offers no item on power saving.