[Intel-gfx] [BUG] i915 HDMI connector status is connected after disconnection

[Chris Wilson]

Quoting Jani Nikula (2018-07-05 09:58:57)
> On Thu, 05 Jul 2018, Chris Chiu <chiu at endlessm.com> wrote:
> > Hi,
> >     We have few ASUS laptops X705FD (The new WiskyLake), X560UD (intel
> > i5-8250U), X530UN (intel i7-8550U) share the same problem, which is
> > the HDMI connector status stays connected even the HDMI cable has been
> > unplugged. Look into the "/sys/class/drm/card0-HDMI-A-1/status" for
> > checking the status while plug/unplug the HDMI, it shows
> > "disconnected" before plug in HDMI cable, then switch to "connected"
> > after plugin, and still stay "connected" after unplug. This would
> > cause the audio output path cannot correctly switch from HDMI to
> > internal speaker after unplugging the HDMI.
> >
> > I then try to verify with the latest kernel 4.18.0-rc3+, the bug still
> > present. The full "dmesg" log is here.
> > https://gist.github.com/mschiu77/d761d7c5cf191b7868d4d7788ae087f1
> >
> > The HDMI cable is plugged in at ~26th second.
> > "[ 26.214371] [drm:drm_detect_monitor_audio [drm]] Monitor has basic
> > audio support"
> > then unplug the HDMI at ~73th second.
> > "[ 73.328361] [drm:drm_detect_monitor_audio [drm]] Monitor has basic
> > audio support"
> >
> > Please advise what I can do to fix this. Thanks
> 
> Seems rather odd. Please file a bug report at [1]. Attach the dmesg on
> the bug. Please attach 'xrandr --verbose' output before and after
> unplugging on the bug.

Note that 'xrandr --verbose' will trigger a reprobe of the devices,
papering over any missed probe following hotplug.  I would suggest
preceding with 'xrandr --current --verbose'.

If all you are doing is checking status, you need to 'echo detect >
status' to trigger a reprobe after hotplug.
-Chris