Created attachment 222091 [details] dmesg for just modprobe nouveau OS: Arch Linux Video adapter: GeForce GTX 780 Ti Since 4.7 loading nouveau module results in black screen, but when I load nouveau module with parameter debug=trace the issue does not appear, screen successfully switches to correct resolution and Xorg can be successfully started. I did following: - after OS booting I issued command "modprobe nouveau", in this case execution of the command took about 44 seconds; - when "modprobe nouveau" returned control to shell I blindly issued command "startx" on terminal in VT; - after that machine was rebooted with "reboot" - after reboot I issued command "modprobe nouveau debug=trace", it took about 11 seconds to finish; - after that I issued "startx" and Xorg started sucessfully. If I compile nouveau module in kernel then I lose video output right after kernel loads if I don't pass nouveau.debug=trace parameter.
Created attachment 222101 [details] Xorg.0.log for modprobe nouveau
Created attachment 222111 [details] dmesg for modprobe nouveau debug=trace
Created attachment 222121 [details] Xorg.0.log for modprobe nouveau debug=trace
Created attachment 222131 [details] lspci
Did this ever work for you? Looks like DP link training fails. If it worked before, I would suspect commit a8953c52b95167b5d21a66f0859751570271d834 .
It works good on kernel 4.6.3 and earlier, problem is since 4.7. I just tried to find conditions of the bug. I reverted patch "0006-drm-nouveau-disp-sor-gf119-both-links-use-the-same-training register" from commit a8953c52b95167b5d21a66f0859751570271d834 and nouveau loads about 1 second, screen does not become black. System behaves like on 4.6 kernel. Unfortunately I can't fully understand impact of this reversion on different video adapters. Can you send it to dri-devel mailing list?
Created attachment 222141 [details] dmesg with reverted 6th patch from a8953c52b95167b5d21a66f0859751570271d834
Ben has a better fix here: https://github.com/skeggsb/linux/commit/217215041b9285af2193a755b56a8f3ed408bfe2
Thank you, that fix helped.
commit 1d110cf5d307bd52e826a2ceaa7daab83be61b7a Merge: cc23c61 39c8859 Author: Linus Torvalds <torvalds@linux-foundation.org> Date: Fri Jul 8 08:55:27 2016 -0700