<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO - [bdw edp] Screen Flickering" href="https://bugs.freedesktop.org/show_bug.cgi?id=91393#c90">Comment # 90</a> on <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO - [bdw edp] Screen Flickering" href="https://bugs.freedesktop.org/show_bug.cgi?id=91393">bug 91393</a> from <a class="email" href="mailto:mika.kahola@intel.com" title="Mika Kahola <mika.kahola@intel.com>"> Mika Kahola</a> <pre>Created <a href="attachment.cgi?id=122497" name="attach_122497" title="Cache DP signal levels">attachment 122497</a> <a href="attachment.cgi?id=122497&action=edit" title="Cache DP signal levels">[details]</a> <a href='page.cgi?id=splinter.html&bug=91393&attachment=122497'>[review]</a> Cache DP signal levels In your case, when DP link is retrained with the settings from previous link training the clock recovery fails. This leads into a situation where link training is started from scratch. However, now the clock recovery seems to be happy with the lower voltage swing and pre-emphasis settings than with the first iteration round. You may experience flickering due to this as the physical link may require higher voltage swing or pre-emphasis than provided. We could try the following trick here. Let's cache the signal levels and in case of link retraining we retrain the link until we have reached the previously trained signal levels and clock recovery is reached. Please, give this a go on top of the latest drm-intel-nightly with these 3 patches applied. Dmesg logs are appreciated too ;)</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> <li>You are on the CC list for the bug.</li> </ul> </body> </html>