| Summary: | [SKL] Black screen on 4.15-rc6 (DP link training error) [regression] | ||||||||
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| Product: | DRI | Reporter: | Direx <direx> | ||||||
| Component: | DRM/Intel | Assignee: | Intel GFX Bugs mailing list <intel-gfx-bugs> | ||||||
| Status: | CLOSED FIXED | QA Contact: | Intel GFX Bugs mailing list <intel-gfx-bugs> | ||||||
| Severity: | major | ||||||||
| Priority: | high | CC: | intel-gfx-bugs | ||||||
| Version: | DRI git | Keywords: | bisect_pending | ||||||
| Hardware: | x86-64 (AMD64) | ||||||||
| OS: | Linux (All) | ||||||||
| Whiteboard: | |||||||||
| i915 platform: | SKL | i915 features: | display/DP, display/DP MST | ||||||
| Attachments: |
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FYI: The issue is about DP-3 (DP2-1 in X11). eDP1 is working. Created attachment 136515 [details] Full kernel debug log (with DMC 1.27) I managed to get a full debug log, which should be more helpful. Meanwhile I have also applied https://patchwork.freedesktop.org/patch/187559/ (the log is with new DMC 1.27), but it does not change anything. But in case a log without that patch is required (DMC 1.26) let me know. Hello Direx, is it possible for you to bisect to find the culprit commit?? Thank you. Sorry, I am neither a kernel developer nor a git expert, just an enthusiast end user. I've tried fiddling with git, but after all the rebasing in drm-intel I have difficulties bisecting. All I can say is that 069d40f5834ad26a58f269225a7e13af17019062 is a good commit and 5ea2355a100a3c6304901d058aee06d3a6be69bc is a bad commit. As reference: good: commit 069d40f5834ad26a58f269225a7e13af17019062 Author: Imre Deak <imre.deak@intel.com> Date: Tue Oct 3 12:51:59 2017 +0300 drm/i915/glk: Fix DMC/DC state idleness calculation bad: commit 5ea2355a100a3c6304901d058aee06d3a6be69bc Author: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com> Date: Tue Oct 3 17:22:11 2017 +0300 drm/i915/mst: Use MST sideband message transactions for dpms control This has been fixed today by: commit 30414f3010aff95ffdb6bed7b9dce62cde94fdc7 Author: Lucas De Marchi <lucas.demarchi@intel.com> Date: Tue Jan 2 12:18:37 2018 -0800 drm/i915: Apply Display WA #1183 on skl, kbl, and cfl Maybe you want to add a test for this, so I am leaving the bug open. Thanks for the follow-up, closing. |
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Created attachment 136486 [details] DP link training errors in dmesg with drm.debug=0x1e I've just booted 4.15-rc6 and I am getting a black external screen (Thinkpad L460 with Ultra Dock and external DP monitor). Stable Kernels (4.14 and older) work just fine. The dmesg is flooded with link training errors, so I was unable to capture a full system log through SSH. The attached dmesg lines are the last link training messages with drm.debug=0x1e. Thousands of these messages appear every second. The messages appear right when modesetting kicks in, before Wayland is starting. This is a major issue, as this is a regression which cause DP displays to fail. My Configuration: - Thinkpad L460 with Ultra Dock (contains a DP MST hub) - External DP monitor connected to Ultra Dock - Arch Linux - Kernel 4.15-rc6 - Intel Core i5-6200U