HDMI is not detected with kernel 4.4

[aymanalz]

Since I installed Linux kernel 4.4 (the current mainstream one), Kubuntu/KDE does not detect the tv screen, connected through hdmi. Settings -> Displa configuration shows only the laptop screen. I did not have this problem with kernel 4.3, or any previous kernel. What could be the issue?

Laptop specs: Intel i7 3612QM, HD-4000 (ivy bridge), Kubuntu 15.10 (wily). Also have Nvidia Geforce 630m, which is not activated, since intel-hd is the default. Mesa 11.0.2.

[claydoh]

the mainline kernels are very generic and may not have everything baked-in. Likely you'd have to recompile drivers and/or parts of the graphics stack to be compatible with them


https://wiki.ubuntu.com/Kernel/Mainl...nel_builds.3F\

Does the kernel team support the mainline kernel builds?
The mainline kernels builds are produced for debugging purposes and therefore come with no support. Use them at your own risk.

https://wiki.ubuntu.com/Kernel/Mainl...s#Introduction :

These kernels are not supported and are not appropriate for production use.

A bit more thorough explanation here:
Should I upgrade to the “mainline” kernels?

[aymanalz]

I'm not sure if 'mainline' is the correct word. 4.4 is the current stable release at kernel.org, and is also available for download from Ubuntu's official PPA. I tried updating Intel drivers using 'Intel graphics installer'. But HDMI is still not detected. I booted using nvidia also, and still it is undetected. On windows, hdmi is detected, and works.

[claydoh]

Which official ppa are you using? I'll bet it is using the above mainline kernels, and as such all the caveats are still relevant. official does not necessarily equal supported, or for daily consumption.

Sure the official kernel may be stable, but it still needs to be built specifically for an Ubuntu system, also some drivers may not be ready or compatible yet with it.

[Snowhog]

January 10, 2016, Linux Kernel 4.4 LTS was released. However, it is available in *buntu 16.04 (Xenial Xerus), not earlier *buntu releases. It could be some time; if ever; before it is back-ported (?) to 15.10.

[claydoh]

January 10, 2016, Linux Kernel 4.4 LTS was released. However, it is available in *buntu 16.04 (Xenial Xerus), not earlier *buntu releases. It could be some time; if ever; before it is back-ported (?) to 15.10.

Where is it in Xenial? I am not seeing it yet, though it should be coming down the pike.
This kernel, when it does make it to 16.04, will be available to previous LTS releases via the hardware-enablement stack, it won't be likely backported to 15.10 which goes EOL this July.

[Snowhog]

Pre-released updates repository.

[claydoh]

ahh... thought I had that turned on, seems I didn't