[Bug 109112] "*ERROR* Failed to probe lspcon" when HDMI isn't plugged before boot

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=109112

--- Comment #34 from shashank.sharma at intel.com <shashank.sharma at intel.com> ---
In the motherboard down mode, LSPCON is supposed to be powered on with the
power supply from the board, and hence, it was supposed to be powered-on during
the driver probe time. So if it's not getting powered on during probe, this
seems like a board design error, and not a SW issue. (This is probably
expecting LSPCON to work in dongle mode, which we do not support in driver).
That also explains why we are not able to reproduce this issue with other
parade based devices.

In order to work around this issue, we can add LSPCON probing in the hot-plug
sequence, but that might come up with its own hotplug stability issues, like if
the I2C over Aux bus is not stable yet, that might delay the hotplug handling
path by adding some retries.

Also, this is only possible when the display master IRQ is getting the HPD
interrupt, but it's getting missed due to unavailability on the connector on
port. But as the IRQ signal is also coming via LSPCON, which is not powered-on
until hotplug, there is also a possibility of missing the hotplug all-together,
in which case, moving the probe is not going to help at all.

- Shashank

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