Your system information

• Steam client version (build number or date): 2813462
• Distribution (e.g. Ubuntu): Ubuntu 16.04 64 bit
• Graphics driver version (run nvidia-settings): 396.24 (Nvidia GTX 1060)
• Gist for SteamVR System Information: https://gist.github.com/asymingt/9e3baf22b1302762ca1126b982be4eb8
• Opted into Steam client beta? Yes
• Opted into SteamVR beta?: Yes
• Have you checked for system updates?: Yes

Please describe your issue in as much detail as possible:

When the screens are in portrait mode, launching SteamVR always causes all screens to turn black and the system to freeze. I cannot even use ctrl+alt+F1 to switch to a console. Sometimes a frozen chaperone is displayed in the HMD, which then occasionally disappears. My only option is to reboot. This does not happen when the screens are configured in landscape mode. Changing the HMD from DP to HDMI has no effect. Reverting to a 388.xx driver version has no effect. It appears that SteamVR requires all monitors to be configure in landscape mode.

Steps for reproducing this issue:

1. Configure screens to portrait mode (rotate them in either the OS or the nvida-xconfig GUI)
2. Launch Steam
3. Run SteamVR