Please cherry-pick upstream patch for HDMI on Dell XPS 9360

[Michael Stapelberg]

Connecting the Dell USB-C HDMI/LAN/VGA/USB adapter to my XPS 9360 doesn’t quite work: I could not get my monitor to display a picture at all, regardless of which resolution I tried.

A quick search on the internet revealed this patch: https://lists.freedesktop.org/archives/intel-gfx/2017-March/124077.html. Applying it to the 4.4.0-122 kernel does indeed make the HDMI work

Could you please cherry-pick this patch into the Ubuntu kernel? Thanks!

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1770423

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Joseph Salisbury (jsalisbury)]

It doesn't look like that patch ever made it into mainline. Could you see if another patch in mainline resolves the bug by testing the mainline kernel? It can be downloaded from:

http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.17-rc4/

[Michael Stapelberg (stapelberg+ubuntu)]

Sorry for the late reply. The patch was merged upstream in https://github.com/torvalds/linux/commit/9a86cda07af2c63649932f0a4fc757701ef54c42

[Joseph Salisbury (jsalisbury)]

I built a Xenial test kernel with commit 9a86cda07af2c63649932f0a4fc757701ef54c42. The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1770423

Can you test this kernel and see if it resolves this bug?

Note about installing test kernels:
• If the test kernel is prior to 4.15(Bionic) you need to install the linux-image and linux-image-extra .deb packages.
• If the test kernel is 4.15(Bionic) or newer, you need to install the linux-modules, linux-modules-extra and linux-image-unsigned .deb packages.

Thanks in advance!

[Michael Stapelberg (stapelberg+ubuntu)]

I tested your kernel build, but unfortunately, I still can’t get a picture on the external HDMI with it. Not quite sure why. Perhaps other patches are required, too?

[Joseph Salisbury (jsalisbury)]

When you applied the patch to the 4.4.0-122 kernel did you have to perform any backporting? I had to with my test kernel, so maybe I didn't perform the backport properly.

I'll do some investigating to see if a prereq patch is needed, so we don't have to do any backporting.

[Michael Stapelberg (stapelberg+ubuntu)]

As far as I remember, I did not have to do any backporting.

Thanks for looking into this.

[Joseph Salisbury (jsalisbury)]

I built a v2 Xenial test kernel with commit 9a86cda07af2c63649932f0a4fc757701ef54c42. The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1770423

Can you test this kernel and see if it resolves this bug?

Note about installing test kernels:
• If the test kernel is prior to 4.15(Bionic) you need to install the linux-image and linux-image-extra .deb packages.
• If the test kernel is 4.15(Bionic) or newer, you need to install the linux-modules, linux-modules-extra and linux-image-unsigned .deb packages.

Thanks in advance!

[Michael Stapelberg (stapelberg+ubuntu)]

Thanks for the new kernel build. I installed it, but unfortunately, I still can’t get a picture on the external HDMI with this build either :(

[Joseph Salisbury (jsalisbury)]

Do you happen to have a patch of what you were able to apply and test originally?

[Michael Stapelberg (stapelberg+ubuntu)]

I just rebuilt a kernel with the patch I used back then, but can’t get the external monitor to work with that either :-/.

I think at this point I’ll just wait for Ubuntu 18 to be available and hope that the newer drivers will fix the issue.

Thanks for your time!