Hello there,after updating my Debian Wheezy/Testing to linux kernel 3.2 my screen goes black at boot, too. My system is a Lenovo Thinkpad L420 with an Intel Core i3 (HD3000) inside. The fix posted above (http://lists.freedesktop.org/archives/intel-gfx/2012-January/014332.html) fixes this bug for me.
If you dont want to compile a custom kernel, a temporary workaround is to add "i915.modeset=0" to the grub command line.
Thank You! WANA