Returning to shell breaks Xserver on ATI Raedon Mobility 7500

[Imaboyo]

Good afternoon.

I have a Dell Inspiron 7500 laptop dual-booting Windows XP and Debian Linux
Sarge. Ever since xserver-xorg replaced xserver-xfree86 in the debian
packages I have had problems with the xserver when I try and break from KDE
back to a terminal (ie.ctrl+alt+F1). The xserver does not hang as such, but
when it attempts to change resolution to match that of the terminal I get a
static display in black and white, showing the upper left corner of part of
the KDE desktop. When I F7 back to the kde display a vertical quarter is
repeated 4 times across the screen in very poor quality, with horizontal
lines repeating down the screen. The only way I can recover from these
symptoms is rebooting the laptop via SSH. It is worth mentioning that KDE
works perfectly before trying to switch to a terminal, responding to
resolution changes with no complaints.

The graphics card is an ATI Mobility Radeon 7500 using the "ati" driver
specified when I ran xorg reconfigure. Kernel is a recent build at 2.6.17.8.
The xserver does not report any errors to Xorg.0.log while the problem
occurs, nor does kdm.log:
(**) RADEON(0): RADEONSaveScreen(2)
(**) RADEON(0): EngineRestore (32/32)
(**) RADEON(0): RADEONSwitchMode() !n(**) RADEON(0): EngineRestore (32/32)
(**) RADEON(0): RADEONLeaveVT
(**) RADEON(0): EngineRestore (32/32)
(**) RADEON(0): RADEONRestore
(**) RADEON(0): Ok, leaving now...
(**) RADEON(0): RADEONEnterVT
(II) RADEON(0): [RESUME] Attempting to re-init Radeon hardware.
(II) RADEON(0): [agp] Mode 0x1f000201 [AGP 0x8086/0x1a30; Card
0x1002/0x4c57]
(**) RADEON(0): EngineRestore (32/32)
(**) RADEON(0): EngineRestore (32/32)
(**) RADEON(0): RADEONSaveScreen(2)
(II) Configured Mouse: ps2EnableDataReporting: succeeded

Any help or advice would be greatly appreciated.

Matthew Taylor