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@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@redhat.com Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch Signed-off-by: Jani Nikula jani.nikula@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@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@gmx.de To: Linux Kernel linux-kernel@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 ?