Comment 0 for bug 1764194

Description: Ubuntu 16.04.4 LTS
Release: 16.04

Ubuntu 16.04.4 LTS was installed to some Dell Latitude 5490 & 5590 laptops, originally running BIOS version 1.0.8. The install media and the installed OS was running linux-generic-hwe kernel 4.13.0.

After upgrading BIOS to latest version 1.1.9, the kernel no longer boots: right after loading the i915 drm driver, the screen goes black, and the machine can only be reset or power cycled. This is true for both the installation media, and the OS instance previously installed to the disk and updated to the latest hwe kernel 4.13.0-38.

Specifying 'nomodeset' on the kernel command line works around the problem by disabling the i915 drm driver functionality. In that case, several display driver function are obviously missing (eg GLX & xrandr).

The problem manifested itself even when using the drm upstream latest git-head version. A custom built kernel was used to provide logs for this upstream bug report:
https://bugs.freedesktop.org/show_bug.cgi?id=105549

The upstream Intel developers provided a patch, which was successfully tested by both the original reporter and me.
https://patchwork.freedesktop.org/patch/216371/
https://github.com/freedesktop/drm-tip/commit/f212bf9abe5de9f938fecea7df07046e74052dde

I backported this fix to ubuntu-xenial hwe git-head, and tested the result successfully. I'd like this fix to be added to the ubuntu-xenial linux-generic-hwe kernel.