[Bug 111045] [CI][BAT] igt at kms_chamelium@(hdmi|dp)-hpd-fast - fail - Failed assertion: igt_hotplug_detected(mon, HOTPLUG_TIMEOUT)

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=111045

--- Comment #15 from Imre Deak <imre.deak at intel.com> ---
(In reply to emersion from comment #14)
> (In reply to Imre Deak from comment #6)
> > There could be a chamelium config issue wrt. HDMI, since there is no HDMI
> > sinks connected (even the USBC->HDMI dongle will show up as DP), but the
> > HDMI chamelium subtests are not skipped as they should be. 
> 
> I think the configuration is fine. I routinely run HDMI tests on my DP port
> with lspcon, and configuring .igtrc to map the DUT DP output to the
> Chamelium HDMI input works.

With DP++ connectors that should work (with a DP++->HDMI dongle), but here
we're talking about a USB-C connector which does not have HDMI output support.
The driver doesn't even register an HDMI output for these connector.

You can connect a USB-C connector to an HDMI input via a TypeC-DP-alt->HDMI
dongle, but that is still a DP connector from the driver's and the igt test's
POV, and so all the Chamelium HDMI subtests should be skipped - which is what I
talked about above.

> 
> > However probably all the DP kms_chamelium tests will fail expectedly on
> > DP-alt outputs. 
> 
> Can you elaborate? I'm not sure I understand.

If unplugging a DP-alt display while there is an active modeset on it, and then
replugging the DP-alt display, the HW/FW/driver won't signal the corresponding
plug-in hotplug event until the mode is disabled.

> > The exceptions could be kms_chamelium subtests where the
> > subtest properly handles hotplug events: enables/disables the output
> > according to the connect/disconnect hotplug event it receives. That's not
> > the case atm with most of the kms_chamelium subtests.
> 
> Why is this needed? If a user plugs a USB-C to HDMI dongle, the DRM client
> should see a hotplug event even if the output hasn't been enabled yet, right?

The failing tests do this:

- <have the output enabled>
- unplug the display, keeping the output enabled
- wait/poll for the disconnect status -> success
- replug the display, while the output is still enabled
- wait/poll for the connect status -> fail

This sequence is not supported with DP-alt sinks (like the USB-C to HDMI
dongle), as I described above. 

> Some tests currently assert HPD on the Chamelium side and expect a hotplug.
> Is this supposed not to work with DP-ext?

If there wouldn't be any mode enabled for the whole duration of the sequence,
or the client would enable/disable the mode according to the output's
connected/disconnected status, then all the hotplug uevents, polling would work
as the test expects.

-- 
You are receiving this mail because:
You are the assignee for the bug.
You are on the CC list for the bug.
You are the QA Contact for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/intel-gfx-bugs/attachments/20190704/959b7c87/attachment.html>