I have a stock Debian Jessie install with grub-pc 2.02~beta2-22+deb8u1
on a T400 with Libreboot 20150518 installed.

Boots fine if I just let it auto-boot and don't go to grub command line
(i.e., if it never tries to read/touch (achi1), which is the DVD drive).

If I hit 'c' and get the grub> prompt:

grub> ls

... works FINE, returning immediately if the DVD drive is not in the
ultrabay slot on the T400, but if I boot with the DVD drive in:

grub> ls
#  .... sits for 2-3 minutes

Then returns file listings as expected.

It's clearly related to (achi1), which is the DVD drive, because this:

grub> ls (ahci0,msdos2)/   # as an example

does not hang and returns expected rules.

But, do a:

grub> ls (ahci1)

and it hangs again for 2-3 minutes.

and returns:

error: AHCI transfer timed out.

During the hang, the HD light is illuminated but it never tries to
access the DVD drive.

Behavior is better if you put a DVD or CD into the drive.  The hang is
shorter, only about 30-60 seconds, and then things proceed normally.
You can even ls the files on the DVD or CD from the grub> prompt with:

grub> ls (ahci1)/

The "error: AHCI transfer timed out " never seems to appear when there's
a DVD in the drive.


Now, I read in this thread:
 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=558661

that it's probably a BIOS bug that causes this.  I'm all for blaming
proprietary BIOS for being broken.  But, in this case, I'm using
libreboot 20150208 so it's either a bug in libreboot, or a bug in GRUB.
The libreboot folks suspect it's a GRUB issue. :)