Intel graphics not working after S3 resume on ThinkPad T430

[Kim Twain]

Hi, I'm writing from FreeBSD 10-RELEASE x86_64, installed on a Lenovo
ThinkPad T430 2349H3G (SKU Number: LENOVO_MT_2349) with BIOS version
G1ET99WW (2.59 ).

The APU is an Intel(R) Core(TM) i5-3210M, and I don't have a
second/dedicated gpu installed.

I can enter ACPI s3 successfully, both with "acpiconf -s 3" and "zzz".
I can also resume from S3, but I only get a blank/black screen.
The system however is correctly working, I can see disk activity by
running a find on /, and I can create arbitrary files (and invoke
'reboot', too).

I then installed xorg and gnome2, to try if the problems persists also
with an X session running.

I can't switch back to a tty with xorg running, and yes, the problem
is still present. Moreover, when entering ACPI S3 from X/gnome, I can
see the status led blinking like in a kernel panic before S3 is
entered.

The wiki reports the entire ThinkPad T400 series as working fine both
from a text console and from an xorg session, and resuming without
problems.

How can I help pinpointing the issue?