R: lockup with vidcontrol VESA_800x600

>Hiho! :-)
>
>Yesterday I upgraded to 
>
>FreeBSD hostname 9.0-CURRENT FreeBSD 9.0-CURRENT #28: Sat Jan  8
>17:05:30 CET 2011
>
>and vidcontrol VESA_800x600 stopped working (again). I exchanged emails
>with jkim about a similar problem in February 2010 (vidcontrol
>VESA_800x600 would mangle the screen output), there was no definitive
>resolution, but it started working again sometime around July 2010.
>
>Now however, when I try to set VESA_800x600, my machine seems to 
>lockup. It no longer responds to any input, I cannot ping it and I
>cannot drop to the debugger.
>
>I've tried setting other modes, but trying to set them results in:
>
>obtaining new video mode parameters: operation not supported by device.
>
>graphics card is a:
>
>vgapci0_at_pci0:1:0:0:     class=0x030000 card=0x013a1002 chip=0x514c1002
>rev=0x00 hdr=0x00 vendor     = 'ATI Technologies Inc. / Advanced Micro
>Devices, Inc.' device     = 'Radeon 8500 / 8500LE (R200)'
>    class      = display
>    subclass   = VGA
>
>Any clues what might have changed?
>
>

I had to gave up with VESA.
Before all the changes (feb./mar. 2010) it was working perfectly with 
MODE_280.
Now I have to use MODE_30, because any other higher resolution isn't working 
or it's crashing the machine, as I've reported yet.
I would like to add that yesterday, I left  twice my pc running CURRENT turned 
on while doing other things. And both time on my return it was dead. Not even 
replying to ping.
I had to set blanktime="NO" in /etc/rc.conf. I'm not sure if the problem has 
been introduced recently.
Did you noticed that too?

Barbara