I have likely the same problem with a single external monitor in Jessie. In fact the OS or X is turning down the brightness on the monitors. If you haven't already, simply try increasing brightness.
On Fri, Oct 7, 2016 at 5:28 AM, Floris <jkflo...@dds.nl> wrote: > Op Thu, 06 Oct 2016 15:17:56 +0200 schreef Xxxxxxx Yyyyyyy < > debian-l...@wp.pl>: > > > Hi. > I use HP ProBook 6560b (LVDS1) with 2 external Fujitsus B24T (VGA1, > HDMI2), both connected via docking station. > > OS: debian testing with xfce > > > > LVDS1 - off > > VGA1 - on > > HDMI2 - on > > > > Recent (approx 1 month back) apt-get upgrade (also using latest > debian-testing.iso) made it impossibe to use this configuration. > > I'm asked for a LUKS password, i can see initial on-screen logs but when > Os tries to start X, both monitors goes black (i cannot switch to TTY). > > > > However when one of monitors is unplugged, OS & X starts with no errors, > then i plug the other monitor in and they both works. > > > > Mariusz > > > > create the folder > /var/log/journal > > reboot with both monitors plugged in and let the configuration fail > unplug a monitor, reboot and use > journalctl -b -1 > to read the error messages > > > Floris > >
