[BUG] i915 HDMI connector status is connected after disconnection

[Chris Chiu]

On Thu, Jul 5, 2018 at 5:37 PM, Jani Nikula <jani.nikula at intel.com> wrote:
> On Thu, 05 Jul 2018, Chris Wilson <chris at chris-wilson.co.uk> wrote:
>> 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.

It's interesting that reprobe triggered by 'xrandr --verbose' after unplug will
get the status back to "disconnected". But if I just do 'xrandr
--current --verbose'
before and after unplugging the cable, the output shows the same status
'connected'.

Here's the output of 'xrandr --verbose' before unplugging HDMI
https://gist.github.com/mschiu77/ea2e843078297f344596243418dcdaf7

And the output of 'xrandr --current --verbose' after unplugging the cable
https://gist.github.com/mschiu77/55756c0801046d49cd9bc3f87712b079

Then do 'xrandr --current --verbose' to trigger reprobe, the ouput
https://gist.github.com/mschiu77/72e6ab5438cbe64443300fc4fd71770c

It means that the HDMI unplug not detected by the driver?

Chris

>
> I was curious about the logs seemingly indicating that we can read the
> EDID even after the user says they've unplugged the cable. The updating
> of sysfs status attribute is another matter.
>
> BR,
> Jani.
>
>
> --
> Jani Nikula, Intel Open Source Graphics Center