Comment 27 for bug 1359689

Esokrates, could you try to boot your system after adding 'plymouth:debug' to the kernel command line in grub; and attaching /var/log/plymouth-debug.log; first making sure it doesn't include your passphrase for the disk encryption? If that doesn't trigger the bug, you may need to edit /etc/default/grub to add 'plymouth:debug' there and reconfigure grub.

So, after testing this for a while it looks to me like this is in fact a problem with drm, at least on radeon, and likely on nouveau as well. On my radeon system, it appears that plymouth tries to start the drm renderer and fails because it can't find the right encoder, or CRTC, to notice that the screen is lit -- that is, unless it was already lit and updated as such in drm by going through the grub menu. It asks libdrm for the available encoders, but the currently selected encoder for the connector remains 0; and if I bypass this and have it check the encoder for it's selected crtc, that value is also left at 0.

It seems like upstream linux commit https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/gpu/drm/drm_crtc.c?id=abd69c55dd8f1f71b33b8c6165217f4329db8f25 should help, and in fact if I use the mainline kernel 3.19 rc1, things appear to be working properly; so I've opened a linux task for this issue.