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<b><a class="bz_bug_link
bz_status_NEW "
title="NEW - [HSW] linux next-20170407+ boots to a blank screen"
href="https://bugs.freedesktop.org/show_bug.cgi?id=100755#c2">Comment # 2</a>
on <a class="bz_bug_link
bz_status_NEW "
title="NEW - [HSW] linux next-20170407+ boots to a blank screen"
href="https://bugs.freedesktop.org/show_bug.cgi?id=100755">bug 100755</a>
from <span class="vcard"><a class="email" href="mailto:dhinakaran.pandiyan@intel.com" title="Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>"> <span class="fn">Dhinakaran Pandiyan</span></a>
</span></b>
<pre>The link m_n and data m_n values are different before and after suspend/resume.
My hunch is when you booted with fastboot=1, commit[1] did not reduce data m_n
but did so after suspend/resume.
Before:
[drm:intel_dump_pipe_config] dp m_n: lanes: 2; gmch_m: 2428257, gmch_n:
8388608, link_m: 134903, link_n: 524288, tu: 64
After:
[drm:intel_dump_pipe_config] dp m_n: lanes: 2; gmch_m: 302776, gmch_n: 1048576,
link_m: 33641, link_n: 131072, tu: 64
Try reverting this -
commit 9a86cda07af2c63649932f0a4fc757701ef54c42
Author: Jani Nikula <<a href="mailto:jani.nikula@intel.com">jani.nikula@intel.com</a>>
Date: Mon Mar 27 14:33:25 2017 +0300
drm/i915/dp: reduce link M/N parameters
Several major vendor USB-C->HDMI converters, in particular the DA200,
fail to recover a 5.4 GHz 1 lane signal if the link N is greater than
0x80000.</pre>
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