I have a nexus 5 with latest nightly CM.
I just received a slimport adapter, and when using it with working hdmi cable(i use the hdmi cable on my computer without an issue), whenever I turn the phone horizontal and the display turns horizontal, i start getting video and audio corruption, and large portions of grey lines on the output, but not the phone display.
It works fine vertical.
Any ideas? Is the adapter corrupted? I literally can rotate the phone back to vertical and it works fine.