As reported upstream, when I used the drm-tip kernel I didn't see the FIFO error message in the logs again (but still had random power downs).
I'm running the mainline kernel 4.15.0-041500rc8-generic and also don't see any of the described issues anymore (although I still have 1-2 random shutdowns per week while the notebook sits in the dock unattended, but there is currently no hint that it's related to the Intel driver).
As reported upstream, when I used the drm-tip kernel I didn't see the FIFO error message in the logs again (but still had random power downs). 041500rc8- generic and also don't see any of the described issues anymore (although I still have 1-2 random shutdowns per week while the notebook sits in the dock unattended, but there is currently no hint that it's related to the Intel driver).
I'm running the mainline kernel 4.15.0-