<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_ASSIGNED " title="ASSIGNED - [GLK] [IGT] testdisplay -a shows corruption on HDMI 4k display" href="https://bugs.freedesktop.org/show_bug.cgi?id=100440#c19">Comment # 19</a> on <a class="bz_bug_link bz_status_ASSIGNED " title="ASSIGNED - [GLK] [IGT] testdisplay -a shows corruption on HDMI 4k display" href="https://bugs.freedesktop.org/show_bug.cgi?id=100440">bug 100440</a> from <a class="email" href="mailto:conselvan2@gmail.com" title="Ander Conselvan de Oliveira <conselvan2@gmail.com>"> Ander Conselvan de Oliveira</a> <pre>(In reply to Luis Botello from <a href="show_bug.cgi?id=100440#c18">comment #18</a>) > After testing testdisplay on HDMI I am getting "No Signal" on HDMI screen > while test sets CRTC(36):[7] 2560x1440 60 2560 2608 2640 2720 1440 1443 > 1448 1481 0x9 0x40. This seems related to HDMI 2.0 high TMDS clock ratio. If I force the driver to not enable the tmds clock ratio, that mode works. I tested custom modes based on the failing one but changing the clock. If the port clock was below 340, then the driver doesn't enable scrambling and the monitor is able to display image. With port clock between [340,405) I got no signal. With port clock >= 405, there was image on the screen. Curiously, if I forced 8 bpc and let scrambling and high tmds clock ratio be enabled normally, the following mode worked: ./testdisplay -f "362.25,2560,2608,2640,4080,1440,1443,1448,1481" -o 68 I also tested enabling the given mode with only scrambling and only high tmds. scrambling high tmds result yes yes fail yes no pass no yes fail no no pass So this seems to be a combination of 12 bpc, a port clock in the range [340,405) and high tmds ratios. But as far as I can tell, we are following the spec with respect to those. Shashank, any ideas?</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>