[REGRESSION] HDMI connector detection broken in 6.3 on Intel(R) Celeron(R) N3060 integrated graphics

[Jani Nikula]

On Fri, 11 Aug 2023, Thorsten Leemhuis <regressions at leemhuis.info> wrote:
> [CCing the i915 maintainers and the dri maintainers]
>
> Hi, Thorsten here, the Linux kernel's regression tracker.
>
> On 10.08.23 21:33, Mikhail Rudenko wrote:
>> The following is a copy an issue I posted to drm/i915 gitlab [1] two
>> months ago. I repost it to the mailing lists in hope that it will help
>> the right people pay attention to it.
>
> Thx for your report. Wonder why Dmitry (who authored a4e771729a51) or
> Thomas (who committed it) it didn't look into this, but maybe the i915
> devs didn't forward the report to them.

It was [1], but never followed up on, and fell between the cracks. :(


BR,
Jani.

[1] https://lore.kernel.org/r/ZGIraoocR1gLCWjZ@intel.com

> Let's see if these mails help. Just wondering: does reverting
> a4e771729a51 from 6.5-rc5 or drm-tip help as well?
>
> BTW, there was an earlier report about a problem with a4e771729a51 that
> afaics was never addressed, but it might be unrelated.
>
> https://lore.kernel.org/all/20230328023129.3596968-1-zhouzongmin@kylinos.cn/
>
> Ciao, Thorsten
>
>> After kernel upgrade from 6.2.13 to 6.3 HDMI connector detection is
>> broken for me. Issue is 100% reproducible:
>> 
>> 1. Start system as usual with HDMI connected.
>> 2. Disconnect HDMI
>> 3. Connect HDMI back
>> 4. Get "no signal" on display, connector status in sysfs is disconnected
>> 
>> Curiously, running xrandr over ssh like
>> 
>>     ssh qnap251.local env DISPLAY=:0 xrandr
>> 
>> makes display come back. drm-tip tip is affected as well (last test
>> 2023-08-02).
>> 
>> Bisecting points at a4e771729a51 ("drm/probe_helper: sort out poll_running vs poll_enabled").
>> Reverting that commit on top of 6.3 fixes the issue for me.
>> 
>> System information:
>> * System architecture: x86_64
>> * Kernel version: 6.3.arch1
>> * Linux distribution: Arch Linux
>> * Machine: QNAP TS-251A, CPU: Intel(R) Celeron(R) CPU N3060 @ 1.60GHz
>> * Display connector: single HDMI display
>> * dmesg with debug information (captured on drm-tip, following above 4 steps): [2]
>> * xrandr output:
>> 
>>     Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 16384 x 16384
>>     DP-1 disconnected (normal left inverted right x axis y axis)
>>     HDMI-1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 708mm x 398mm
>>        1920x1080     60.00*+  50.00    59.94    30.00    25.00    24.00    29.97    23.98
>>        1920x1080i    60.00    50.00    59.94
>>        1360x768      59.80
>>        1280x768      60.35
>>        1280x720      60.00    50.00    59.94
>>        1024x768      75.03    70.07    60.00
>>        832x624       74.55
>>        800x600       75.00    60.32
>>        720x576       50.00
>>        720x480       60.00    59.94
>>        640x480       75.00    60.00    59.94
>>        720x400       70.08
>>     DP-2 disconnected (normal left inverted right x axis y axis)
>>     HDMI-2 disconnected (normal left inverted right x axis y axis)```
>> 
>> I'm willing to provide additional information and/or test fixes.
>> 
>> [1] https://gitlab.freedesktop.org/drm/intel/-/issues/8451
>> [2] https://gitlab.freedesktop.org/drm/intel/uploads/fda7aff0b13ef20962856c2c7be51544/dmesg.txt
>> 
>> #regzbot introduced: a4e771729a51
>> 
>> --
>> Best regards,
>> Mikhail Rudenko

-- 
Jani Nikula, Intel Open Source Graphics Center