Comment 8 for bug 430694

with the workaround, it also worked for me with i915.modeset=1 set to grub. But with the last kernel-update i run again in the error. workaround wasn't working for me. at the end, this helped me in /etc/initramfs-tools/modules

...
fbcon
intel_agp
agpgart

i think fbcon is not needed anymore, was another workaround for black screen

>has anyone got a clue why this only affects every Xth boot?
i think the problem is, when initrd gets updated. maybe dependencies of the modules were not set correctly and drm is complied (and loaded) into kernel before agpgart-intel