<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO - System hangs when some video output is disabled/enabled on Skylake platform in double/triple display configuration" href="https://bugs.freedesktop.org/show_bug.cgi?id=94822#c4">Comment # 4</a> on <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO - System hangs when some video output is disabled/enabled on Skylake platform in double/triple display configuration" href="https://bugs.freedesktop.org/show_bug.cgi?id=94822">bug 94822</a> from <a class="email" href="mailto:echerkasov@dev.rtsoft.ru" title="Edgar Cherkasov <echerkasov@dev.rtsoft.ru>"> Edgar Cherkasov</a> <pre>(In reply to Jim Bride from <a href="show_bug.cgi?id=94822#c3">comment #3</a>) Hi Jim, thanks a lot for your feedback! First of all let me inform your regarding the state of the main problem(Linux hangs when video output is disabled/enabled during boot) - it can't be reproduced with vanilla 4.6.rc5 kernel. And please find answers to your questions below: > There are a couple of odd things that I’ve seen while looking over the first > dmesg log. The first is that the sink devices advertise that they only > support up to 2.7Gbps transfer rate, which makes me suspect that they are > older models. Could you please tell us the make and model numbers of the > displays in question? This can be caused by our DP to VGA and DP to DVI converters. If needed I can repeat the test using a "pure" DP display without any converters. Description of our current h/w configuration: 1) First DDI output -> DP to DVI-I converter(Chrontel CH7318C) -> DVI display(Acer V223W); 2) Second DDI output -> DP to VGA converter(noname) -> VGA display(RoverScan JM678); 3) eDP output -> on-board eDP to LVDS converter(PTN3460) -> LVDS display(LG LB121S03). > The second is that there are quite a number of > watermark WARNs. The kernel log lists the version as 4.6.999, so I really > don’t have a clue specifically how recent this is, and I have to assume that > it’s based on the kernel.org kernel. These tests were performed with the latest at that time(first days of April) version of drm-intel-nightly from prebuilt Ubuntu repository: <a href="http://kernel.ubuntu.com/~kernel-ppa/mainline/drm-intel-nightly/">http://kernel.ubuntu.com/~kernel-ppa/mainline/drm-intel-nightly/</a> If needed, I can try to find the exact version. > There have been some fixes in the > watermarking area recently, so it would be helpful to try and reproduce this > issue using the same hardware and drm-intel-nightly (assuming this is not > drm-intel with the version info changed.) I've tried the latest drm-intel-nightly from the same Ubuntu repository: cod/tip/drm-intel-nightly/2016-05-05 bbb6a0d936b5648b31f173d47f93f389a6c6b653 and, unfortunately, all the same - system hangs during the execution of kms_plane test from intel-gpu-tools. The only difference is broken S3(but it does not relate to Intel drm). Please find logs in the attachment. > Finally, although the stated > reason for the patches referenced in the thread is DP MST, it might be worth > trying the two attached patches on top of drm-intel-nightly, assuming the > problem reproduces against that kernel. The issue being fixed is > exacerbated by MST, but it is a general racy problem with the frame buffer > connector counting if I’m interpreting the information correctly. Thanks! I will give it a try and provide a feedback in 1-2 days. Summary: As the problem can't be reproduced on vanilla 4.6.rc5 kernel, the bug can be closed, but: - I still want to test the attached patches and provide feedback; - please tell if additional experiments/information are needed(testing on pure DP display, testing different kernels, different versions of drm-intel-nightly, ...). Best regards, Edgar Cherkasov.</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 assignee for the bug.</li> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>