<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - [BAT][SKL] *ERROR* failed to enable link training" href="https://bugs.freedesktop.org/show_bug.cgi?id=101144#c21">Comment # 21</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - [BAT][SKL] *ERROR* failed to enable link training" href="https://bugs.freedesktop.org/show_bug.cgi?id=101144">bug 101144</a> from <a class="email" href="mailto:marta.lofstedt@intel.com" title="Marta Löfstedt <marta.lofstedt@intel.com>"> Marta Löfstedt</a> <pre>(In reply to Ville Syrjala from <a href="show_bug.cgi?id=101144#c16">comment #16</a>) > One peculiar thing see in some of the logs at least is a double long HPD > when we turn on the panel. I wonder if there's some kind of transient glitch > on the VDD line or something that causes to panel to do some kind of > off->on->off->on transition. > > To get some more debug information maybe someone could hack up a test patch > that checks the state of the HPD pin in a few places during the modeset; Eg. > just after the panel supposedly powered on and just before starting link > training, and maybe in a few places in between. > > What kind of machine is this? I'm wondering of the panel power delays might > be off somehow, eg. the power cycle delay might be too short and the panel > doesn't like it if we power it back up too soon... Ville, I have looked through a lot of the dmesg and this double long HPD thing appear to always happen before we get the aux timeout and after that the link training dmesg-warn (and after that the <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO - [BAT][SKL] igt@kms_flip@basic-flip-vs-dpms produces a dmesg-fail" href="show_bug.cgi?id=101167">bug 101167</a> issue), actually I have even seen 3 long HPDs in a short time.</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>