<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_REOPENED " title="REOPENED - [i9xx TV][BISECT] vblank wait timeout on crtc" href="https://bugs.freedesktop.org/show_bug.cgi?id=93782#c26">Comment # 26</a> on <a class="bz_bug_link bz_status_REOPENED " title="REOPENED - [i9xx TV][BISECT] vblank wait timeout on crtc" href="https://bugs.freedesktop.org/show_bug.cgi?id=93782">bug 93782</a> from <a class="email" href="mailto:mariusz.g.mazur@gmail.com" title="Mariusz Mazur <mariusz.g.mazur@gmail.com>"> Mariusz Mazur</a> <pre>Ah, progress, thanks for that. Based on your comment I've snooped around the code, and found this in drivers/gpu/drm/i915/intel_tv.c: /* For unknown reasons the hw barfs if we don't do this vblank wait. */ intel_wait_for_vblank(dev, intel_crtc->pipe); along with the commit log for it (bf2125e2f7e931b50a6c76ba0435ba001409ccbf): drm/i915: wait for a vblank to pass after tv detect Otherwise the hw will get confused and result in a black screen. (…) v2: As suggested by Chris Wilson, add a small comment to ensure that no one accidentally removes this vblank wait again - there really seems to be no sane explanation for why we need it, but it is required. Which leads me to believe that if I figure out a few places in the code to sprinkle intel_wait_for_vblank() calls, it might fix the issue. I'll get my lucky dice and get right to it.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are on the CC list for the bug.</li> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>