Level1Tech KVM won't wake up Ubuntu

Level1Techs INBOX.deb
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Hey gang,

I got my 1.4 Display Port KVM Switch - Dual Monitor - Two Computer and couldn’t be happier - it switches snappily between my Windows box and MacBook Pro 14 M1, driving two monitors, one of them at 4K @ 144Hz (weirdly Mac only goes up to 99Hz).

Story changes however when I reboot to Ubuntu - it works fine, but when I switch to Mac and back, screens completely refuse to wake up, as if they are not there.

The configuration is as follows:

  • MSI Tomohawk B450 mobo
  • RTX 2070 graphics card
  • Amazon Basics DP 1.4 cables running from graphic cards to KVM and onwards to monitors
  • Ubuntu 22.04 with NVidia drivers installed from NVidia website

FWIW this particular problem did not manifest with my old (ATEN) KVM.

Any ideas what could be going here?

Thanks!

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@wendell

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anything useful in journalctl -xe or dmesg? like the display driver crashing?

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So my current working hypothesis was that the problem was with nouveau driver - at some point Ubuntu for some reason decided that having NVidia drivers is a bad idea and reverted to nouveau. Upon taking considerable time to disable and blacklist it, things returned to normal. This is working fine now, will be continuing to monitor

It was actually message from @wendell that prompted me to ssh into the box and look at dmesg - where I spotted nouveau messages all over the place, so kudos for that!

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