External Monitor enters Power Save
by pschmitt from LinuxQuestions.org on (#4W2N3)
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.
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.