I recently upgraded to a Dell XPS 13 for my development machine at work (Lovely hardware, with official Ubuntu support from Dell) and it’s been great. The only fly in the ointment has been the Dell DA200 mini usb-c adapter that provides ethernet, USB, VGA and HDMI connectors. Due to a bug in the firmware for the adapter, the HDMI connection doesn’t work under linux except at very low resolutions.

Thankfully there is a fix available in the kernel from 4.11 onwards, but I’m running Ubuntu 16.10 with kernel 4.8. Luckily there is a patch containing the fix that can be applied and compiled as a DKMS module. This means that I can make use of the fix now, without having to wait until I upgrade to a newer kernel. The instructions for applying the patch are outlined in the bug report but they’re a bit disjointed, so I’ve collected them here to simplify the process for others.

First, open a terminal and get an interactive root shell, then install & extract the kernel sources:

sudo -i
apt-get install linux-source-4.8.0
cd /usr/src/
tar -jxf linux-source-4.8.0.tar.bz2

Then copy the existing i915 driver and create a DKMS configuration for it:

cp -R ./linux-source-4.8.0/drivers/gpu/drm/i915 ./i915-usbc
cd i915-usbc/
cat << EOF > dkms.conf
sed -i 's#../../../platform/x86/intel_ips.h#../../linux-source-4.8.0/drivers/platform/x86/intel_ips.h#g' intel_pm.c

The last line is just adjusting the path for an include statement.

Finally download and apply the patch before building the dkms module:

wget https://patchwork.freedesktop.org/patch/145853/raw/ -O /tmp/drm-i915.patch
patch -p5 < /tmp/drm-i915.patch
dkms add -m i915 -v usbc
dkms build -m i915 -v usbc
dkms install -m i915 -v usbc

Then reboot and the HDMI adapter will work as intended at all resolutions.