Description of problem:
Screen randomly blackens with no apparent reason
Comes back after a few mouse clicks


Version-Release number of selected component (if applicable):
F11 (upgraded from F10)
issue reproduced on two systems - lenovo T400 running F11 x64 and dell latitude d520 running F11 i386

How reproducible:
one every few hours

Steps to Reproduce:
1.
2.
3.
  
Actual results:
screen goes black

Expected results:
no screen glitches

Additional info:
nothing in /var/log/messages or in dmesg
same happens when working with laptop or attached external screen
#uname -a
Linux dy-lappie 2.6.29.6-213.fc11.x86_64 #1 SMP Tue Jul 7 21:02:57 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux

# lsmod |grep -i intel
snd_hda_intel          29000  1 
snd_hda_codec          65376  2 snd_hda_codec_conexant,snd_hda_intel
snd_pcm                79352  2 snd_hda_intel,snd_hda_codec
snd                    65096  8 snd_hda_codec_conexant,snd_hda_intel,snd_hda_codec,snd_hwdep,snd_pcm,snd_timer
snd_page_alloc          9216  2 snd_hda_intel,snd_pcm