monitor blanks ... input with kern.4.4 [SOLVED Hardware]

albright · Last edited by albright on Wed May 18, 2016 2:47 pm; edited 3 times in total

Hi all - this is a strange problem and may be unique to me

I have an intel NUC5i7RYB

Since install kernel >4.4.0 I have the strange sympotm that
when I press the keyboard the screen goes blank for a second.
This doesn't *always* happen.

No error messages appear in syslog or .xsessionerrors.

My system is weird because it has a device that splits the mini dp output
to two displayports for dual monitor support (which works fine).

NOte that it is the screen on which the active app (the one I am using
the keyboard to enter data) that goes blank.

As I said this does not happen with kernels < 4.4.0

I should say that I'm mostly running kde 5 but the same thing happens
in a LXDE session.

So I'm just throwing this question out in case anybody has had a similar
problem and might have some advice.
_________________
.... there is nothing - absolutely nothing - half so much worth
doing as simply messing about with Linux ...
(apologies to Kenneth Graeme)

albright · Posted: Mon Feb 01, 2016 6:36 pm Post subject:

problem still there with kernel 4.4.1

I upgraded 4.3.2 to 4.3.5 without the graphics glitch appearing so it
seems to be a 4.4 issue

nothing in logs or .xsessionerros and it happens with input
(mouse moving over window or sometimes keyboard press)
_________________
.... there is nothing - absolutely nothing - half so much worth
doing as simply messing about with Linux ...
(apologies to Kenneth Graeme)

toralf · Posted: Mon Feb 01, 2016 6:43 pm Post subject:

4.4.1 is out - if it isn't fixed there you might report this to the appropriate kernel mailing list.

albright · Posted: Fri Feb 19, 2016 3:54 pm Post subject:

still happening on 4.4.2 - there is a kernel bug on this (I think it's the same
problem)

some suggested enabling microcode - did not solve it for me

some suggested switching to uxa acceleration -- this seemed to greatly improve
but not eliminate the problem

typical errors around the time the screen temporarily blanks are this:

albright · Posted: Sat May 07, 2016 3:05 pm Post subject:

running 4.5.3 for a couple of hours without any screen blanking / blinking

hurray - I'll mark this solved
_________________
.... there is nothing - absolutely nothing - half so much worth
doing as simply messing about with Linux ...
(apologies to Kenneth Graeme)

albright · Posted: Thu May 12, 2016 4:55 pm Post subject:

spoke too soon - after rebooting today (after kde update) the problem
is back; really entirely mysterious
_________________
.... there is nothing - absolutely nothing - half so much worth
doing as simply messing about with Linux ...
(apologies to Kenneth Graeme)

albright · Posted: Wed May 18, 2016 2:48 pm Post subject:

FWIW (not much, I know) the problem was with the startech
displayport splitter; when I finally got proper cables to use
DP and HDMI everything worked ...
_________________
.... there is nothing - absolutely nothing - half so much worth
doing as simply messing about with Linux ...
(apologies to Kenneth Graeme)