linux-kernel - Re: [BUG] i915 HDMI connector status is connected after disconnection

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Message-ID: <87bmbmowek.fsf@intel.com>
Date:   Thu, 05 Jul 2018 12:37:55 +0300
From:   Jani Nikula <jani.nikula@...el.com>
To:     Chris Wilson <chris@...is-wilson.co.uk>,
        Chris Chiu <chiu@...lessm.com>,
        David Airlie <airlied@...ux.ie>,
        joonas.lahtinen@...ux.intel.com, rodrigo.vivi@...el.com
Cc:     intel-gfx@...ts.freedesktop.org,
        Linux Upstreaming Team <linux@...lessm.com>,
        Linux Kernel <linux-kernel@...r.kernel.org>,
        dri-devel <dri-devel@...ts.freedesktop.org>
Subject: Re: [BUG] i915 HDMI connector status is connected after disconnection

On Thu, 05 Jul 2018, Chris Wilson <chris@...is-wilson.co.uk> wrote:
> Quoting Jani Nikula (2018-07-05 09:58:57)
>> On Thu, 05 Jul 2018, Chris Chiu <chiu@...lessm.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.

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