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<b><a class="bz_bug_link
bz_status_NEW "
title="NEW - "*ERROR* Failed to probe lspcon" when HDMI isn't plugged before boot"
href="https://bugs.freedesktop.org/show_bug.cgi?id=109112#c35">Comment # 35</a>
on <a class="bz_bug_link
bz_status_NEW "
title="NEW - "*ERROR* Failed to probe lspcon" when HDMI isn't plugged before boot"
href="https://bugs.freedesktop.org/show_bug.cgi?id=109112">bug 109112</a>
from <span class="vcard"><a class="email" href="mailto:kai.heng.feng@canonical.com" title="Kai-Heng Feng <kai.heng.feng@canonical.com>"> <span class="fn">Kai-Heng Feng</span></a>
</span></b>
<pre>(In reply to <a href="mailto:shashank.sharma@intel.com">shashank.sharma@intel.com</a> from <a href="show_bug.cgi?id=109112#c34">comment #34</a>)
<span class="quote">> 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.</span >
Ok we'll let vendor know about this.
<span class="quote">>
> 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.</span >
We can use a DMI based quirk so other platforms won't be penalized.
<span class="quote">>
> 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.</span >
This doesn't explain why Windows doesn't have this issue, it can reliably
detect hot plugging event everytime.
<span class="quote">>
> - Shashank</span ></pre>
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