<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_ASSIGNED " title="ASSIGNED - [APL][Linux]: HDMI / DP are not responding properly in APL" href="https://bugs.freedesktop.org/show_bug.cgi?id=94044#c12">Comment # 12</a> on <a class="bz_bug_link bz_status_ASSIGNED " title="ASSIGNED - [APL][Linux]: HDMI / DP are not responding properly in APL" href="https://bugs.freedesktop.org/show_bug.cgi?id=94044">bug 94044</a> from <a class="email" href="mailto:jim.bride@linux.intel.com" title="Jim Bride <jim.bride@linux.intel.com>"> Jim Bride</a> <pre>There are several things that could be at play here. First off, since we're looking at BXT-P A0, then DDI1 (Port C) cannot be used. If you're plugging monitors in on that port, then the lack of a routed HPD signal to that port will prevent hot plugs from working correctly. Secondly, until LSPCON gets into the kernel DDI0 (Port B) is also not going to behave reliably. I strongly recommend moving to B0 silicon for all external monitor testing, and even then I wouldn't get super excited about it until the LSPCON patches land. One other curious thing I saw: Feb 11 08:36:51 apl kernel: [53111.664336] [drm:intel_dp_compute_config] DP link computation with max lane count 2 max bw 270000 pixel clock 138780KHz Feb 11 08:36:51 apl kernel: [53111.664359] [drm:intel_dp_compute_config] DP link bw 0a rate select 00 lane count 2 clock 270000 bpp 24 Feb 11 08:36:51 apl kernel: [53111.664366] [drm:intel_dp_compute_config] DP link bw required 333072 available 432000 Does the APL panel only support two lanes of DP? I'm also seeing that we're only training at HBR1. Is CDCLK being set in the BIOS, and if so to what value? On SKL+ the CDCLK setting has a direct bearing on how fast the ports can run. In any event, please retest ensuring that CDCLK is set to maximum and then let's see if at least eDP works without flickering in this scenario.</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>