This commits breaks a working configuration here - reverting it let both version 3.18.4 and 3.18.5 working fine again at a hardened Gentoo Linux
commit ddf6f9a4c9fb1c72ea2e8d196c9a580a8e914dbd Author: Dave Airlie <airlied at redhat.com> Date: Mon Dec 8 13:23:37 2014 +1000 drm/i915: resume MST after reading back hw state commit e7d6f7d708290da1b7c92f533444b042c79412e0 upstream. Otherwise the MST resume paths can hit DPMS paths which hit state checker paths, which hit WARN_ON, because the state checker is inconsistent with the hw. This fixes a bunch of WARN_ON's on resume after undocking. Signed-off-by: Dave Airlie <airlied at redhat.com> Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch> Signed-off-by: Jani Nikula <jani.nikula at intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org> On 02/02/2015 07:24 PM, Toralf Förster wrote: > In the mean while I have to correct it - it is reliable. > So something between 3.18.3 and 3.18.4 break a docking system configuration > in that manenr, that after resume the external (iand internal X11 screen) is > black. > > > -------- Forwarded Message -------- > Subject: 3.18.3->4 : external monitor is black after wakeup of a docked > system after s2ram > Date: Sat, 31 Jan 2015 16:47:45 +0100 > From: Toralf Förster <toralf.foerster at gmx.de> > To: Linux Kernel <linux-kernel at vger.kernel.org> > > Happened 2 times here (but not always) that a docked Lenovo T440s (intel > graphic) doesn't show anything at the external display (KDE 4.13.3). System > is a hardened stable 64 bit Gentoo Linux > > Nothing suspicious in the log however. > > Known issue ? > -- Toralf pgp key: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 0076 E94E