I was experiencing this bug on 15.04, and just upgraded to Ubuntu-GNOME 15.10 (kernel 4.2.0-16-generic). The problem with the dm-crypt password on boot is gone, and I am able to boot successfully without patching anything. I do still get a lot of
[drm:gen8_irq_handler [i915]] *ERROR* The master control interrupt lied (SDE)!
I was experiencing this bug on 15.04, and just upgraded to Ubuntu-GNOME 15.10 (kernel 4.2.0-16-generic). The problem with the dm-crypt password on boot is gone, and I am able to boot successfully without patching anything. I do still get a lot of
[drm:gen8_ irq_handler [i915]] *ERROR* The master control interrupt lied (SDE)!
messages in the kernel log though.