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<body><span class="vcard"><a class="email" href="mailto:jani.nikula@intel.com" title="Jani Nikula <jani.nikula@intel.com>"> <span class="fn">Jani Nikula</span></a>
</span> changed
<a class="bz_bug_link
bz_status_NEEDINFO "
title="NEEDINFO - Screen goes blurry after getting hpd irq"
href="https://bugs.freedesktop.org/show_bug.cgi?id=105267">bug 105267</a>
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<table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>What</th>
<th>Removed</th>
<th>Added</th>
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<td style="text-align:right;">i915 platform</td>
<td>
</td>
<td>CFL
</td>
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<td style="text-align:right;">i915 features</td>
<td>
</td>
<td>display/eDP
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<b><a class="bz_bug_link
bz_status_NEEDINFO "
title="NEEDINFO - Screen goes blurry after getting hpd irq"
href="https://bugs.freedesktop.org/show_bug.cgi?id=105267#c5">Comment # 5</a>
on <a class="bz_bug_link
bz_status_NEEDINFO "
title="NEEDINFO - Screen goes blurry after getting hpd irq"
href="https://bugs.freedesktop.org/show_bug.cgi?id=105267">bug 105267</a>
from <span class="vcard"><a class="email" href="mailto:jani.nikula@intel.com" title="Jani Nikula <jani.nikula@intel.com>"> <span class="fn">Jani Nikula</span></a>
</span></b>
<pre>Seems to be a Coffeelake with a Cannonlake PCH. (Mysteriously the device info
is missing from the logs.)
I have no clue about the root cause yet, but what happens is that the eDP panel
signals short pulse hotplug. This indicates the panel requests a link status
check. We do this, and find the link status is in fact not good. To remedy, we
try to re-train the link. The link training succeeds. This is all according to
DP spec. From the logs, there is nothing out of the ordinary. But apparently
the link retraining leads to flickering.
The hotplug occurs at about 71 seconds into the boot. If this is typical, this
should give you enough time to do a modeset (disable/enable display, but don't
suspend/resume) before this happens due to the hotplug. Does this cause
flicker? Or only when the panel requests link status check?
The simple thing (for us) to do is double check the Coffeelake DDI buffer
translations and link training values, especially see if there have been any
recent updates to the specs.
Curiously the VBT refers to Skylake. I'm wondering where the VBT comes from and
whether it's been updated for the platform at hand.</pre>
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