Comment 14 for bug 1657994

I had been trying to cherry-pick patches from the working Xenial kernel to mainline, and got bogged down with build issues. Back to the bisection:

This kernel ...
http://kernel.ubuntu.com/~jsalisbury/lp1657994/linux-image-4.4.0-040400-generic_4.4.0-040400.201702021530_amd64.deb
.. does not work. Failure mode like 4.4 mainline.

I can also update that mainline kernels 4.10.3 and 4.11-rc2 both fail like other recent mainline kernels.

To recap, we have only two working data points, both Xenial kernels (4.4+i915 backport).
4.4.0-59
4.4.0-21

All mainline 4.4 kernels do not even enumerate HDMI audio.

All mainline kernels from 4.5-rc1 and later enumerate HDMI audio but produce no sound.