[Intel-gfx] periodic wakeup from DPMS suspend

[Johannes Stezenbach]

On Tue, Oct 06, 2015 at 11:04:53PM -0400, Alex Deucher wrote:
> On Tue, Oct 6, 2015 at 11:10 AM, Johannes Stezenbach <js at sig21.net> wrote:
> >
> > I have a NEC EA244WMi monitor connected to an Asus P8H77-V
> > mainboard with Ivy Bridge Core i5-3550 via DVI.
> > If DPMS suspend is enabled (by xscreensaver, or for testing by
> > "xset dpms force off/suspend/standby"), the monitor
> > enters standby mode but wakes up every 10...30 seconds for
> > 6 seconds to display a "DVI-D: no signal" message.
> 
> Some monitors periodically scan all of their inputs if they are not
> actively being driven by anything to try and automatically switch to
> the connected input.  When the monitor scans the DVI input, it sees
> load on the pins and turns on, only to realize it's not getting a
> signal and then turns off.  If your monitor has an option to turn off
> input probing, that might help.

It's not like I didn't try to twiddle just about every
available menu item, and also used the monitor's
"Reset to Factory Defaults" to no avail.
However, while trying again I found a hidden menu item
which is only available during the short time the
"No Signal" message is displayed, where the left/right
touch buttons open a "Scan Time" setting with "Normal"
and "Slow" options.  After I changed it, the issue was
solved.  I changed it back and the issue doesn't reproduce.
So it looks some internal configuration of the monitor
was messed up and is now fixed by twiddling the hidden
menu item.  "Scan Time" is not documented in the manual
nor is there an indication in the "No Signal" popup.

Case closed.


Thanks,
Johannes