GTX970, HDMI and SteamOS

Hello, I just installed SteamOS using the GTX970 linux driver.
http://www.nvidia.com/Download/driverResults.aspx/80145/en-us

Everything worked fine, but I have one issue that I don’t know how to tackle. Even though the driver work properly using the DVI/VGA connector: http://www.asus.com/media/global/products/kGuOwdiBWA3ABAUa/GJJ88wObkCNjmcB0_setting_fff_1_90_end_500.png
If I switch to using the HDMI port, SteamOS fails to boot. Under Windows7 this doesn’t seem to be a problem. Any hints to how I might handle this would be highly appreciated. I don’t even know how to start debugging this problem.

Kind regards.

plz provide nvidia bug report by running nvidia-bug-report.sh script as root user. Is that mean when you connect display to hdmi port and start X - X is failed to start ?