Fwd: 3.18.3->4 : external monitor is black after wakeup of a docked system after s2ram

[Toralf Förster]

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