Nouveau and VFIO: A Random Collection of Data Points

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The struggles I faced getting Nouveau + VFIO to work

So, as mentioned in my previous post about VFIO, I’m running nouveau inside of a Linux VM using PCI passthrough. Here are some random tips and notes that I’ve learned.

(Kernel: 4.10-rc8)

  • The system shows “no signal” during modesetting.
    • Workaround: Use nomodeset nouveau.modeset=0 kernel parameters to disable kernel modesetting. This, however, disables the nouveau driver, so you won’t be running any graphical applications.
    • Solution: Use nouveau.config=NvForcePost=1 to force a POST on the graphics card. This seems to fix it.
    • UPDATE 2017-04-17: This doesn’t seem to be VFIO-specific — I have to do it when booting from a live CD anymore.
  • The display shows “no signal” after a reboot when using nouveau’s experimental reclocking.
    • Workaround: Lower the pstate to 07 before rebooting.
  • TTYs are nonfunctional on a dual-monitor setup. (This might not be VFIO-specific.)
    • Solution: Unknown. Bugzilla issue here.
    • UPDATE 2017-04-17: Fixed in the kernel as of 4.11.