Nouveau - Jul 2016 - Displays goes in standby mode on boot when HDMI/DVI used (VM + PCI passthrough)

Hi

I have an issue with a Nvidia GeForce 710 graphic card since several weeks,
probably related to a bug in Nouveau.

Here is my setup :
A Computer based on X58 chipset running Proxmox VE 4.x. The graphic card is
used by a qemu-kvm virtual machine running Debian 9 testing thanks to PCI
passthrough.

The issue : the graphic card has 1 VGA, 1 DVI, 1 HDMI outputs. If a DVI or
HDMI monitor is plugged when the guest OS boots, all connected displays
switch to standby mode, but the guest VM is alive. I can open a ssh session)

I found several workarounds :
- disable framebuffer in the guest OS (therefore disabling Nouveau)
- plug the HDMI or DVI monitor after the guest is ready, and detect the
monitors in XFCE
- install nvidia-driver package (and disable Nouveau)

- disabling framebuffer is not an acceptable option for me.
- unpluging / repluging a monitor est quite annoying, the not an option.
- the nvidia-driver is a non-free package, the I wish to find a better
solution is possible.

Is there an other know orkaround ?

If it is a bug, I need help to gather useful data for developers and fill a
bug report

Thank you very much in advance.
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<https://lists.freedesktop.org/archives/nouveau/attachments/20160703/fd5e76e2/attachment.html>