Any news? The issue still exists with the kernel 5.1-RC1. It works without the
DRM updates 'drm-next-2018-12-14' [1].

Did you modify the behaviour of the initialisation of two graphics cards in the
DRM updates 'drm-next-2018-12-14' [1]?

Please check the DRM updates 'drm-next-2018-12-14' [1].

@Allan
Please test the stable kernel 4.20.16 [2]. I hope the issue wasn't back ported
to the stable kernel 4.20.

[1]
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=4971f090aa7f6ce5daa094ce4334f6618f93a7eb

[2] http://www.xenosoft.de/linux-image-4.20.16-X1000_X5000.tar.gz