Hi, On Sat, Jan 14, 2023 at 07:56:50AM +0100, Greg KH wrote: > On Fri, Jan 13, 2023 at 11:58:47PM -0500, Matthew Fahner wrote: > > Hello, > > > > I'm running Ubuntu 20.10 and experienced a regression when trying > > kernel 6.1.5 that was not present in previous kernels such as 6.0.19 > > or 6.0.9 > > > > I have two monitors attached using DisplayPort MST (daisy chaining the > > displays). > > > > Normally, this works without issue and both monitors are detected and > > display properly. > > > > With kernel 6.1.5, the second monitor (the monitor that's not directly > > connected to the computer) was detected but would not display. I > > didn't spend much time troubleshooting the issue and instead reverted > > to 6.0.19 where it again worked without issue. The first monitor > > worked without issue. > > > > Let me know what steps I can take to help identify the root cause. > > Can you use 'git bisect' to track down the offending commit? Not the reporter, but I suspect this is https://gitlab.freedesktop.org/drm/amd/-/issues/2171 . Matthew can you verify this matches? There is as well context on this issue on this thread: https://lore.kernel.org/stable/8502e5d8-8444-e256-54f3-0c488b54686a@xxxxxxx/ FWIW, we had a similar bugreport downstream in Debian: https://bugs.debian.org/1028451 Regards, Salvatore
