3.7-rc2: corrupted image on Radeon HD 7800 after restarting X

[Frederik Himpe <fhimpe@telenet.be>]

When I restart my display manager (GDM) from tty0, I get a corrupted 
image where parts of the X display before I restarted GDM become visible 
on both the newly started X server instance as on tty0. When moving the 
mouse in X, the current (correct) image around the cursor is replaced by 
the image which was shown before X was started.

01:00.0 VGA compatible controller [0300]: Advanced Micro Devices [AMD] 
nee ATI PITCAIRN PRO [Radeon HD 7800 Series] [1002:6819] (prog-if 00 [VGA 
controller])
	Subsystem: PC Partner Limited Device [174b:e218]
	Flags: bus master, fast devsel, latency 0, IRQ 48
	Memory at e0000000 (64-bit, prefetchable) [size=256M]
	Memory at f7d00000 (64-bit, non-prefetchable) [size=256K]
	I/O ports at e000 [size=256]
	Expansion ROM at f7d40000 [disabled] [size=128K]
	Capabilities: [48] Vendor Specific Information: Len=08 <?>
	Capabilities: [50] Power Management version 3
	Capabilities: [58] Express Legacy Endpoint, MSI 00
	Capabilities: [a0] MSI: Enable+ Count=1/1 Maskable- 64bit+
	Capabilities: [100] Vendor Specific Information: ID=0001 Rev=1 
Len=010 <?>
	Capabilities: [150] Advanced Error Reporting
	Capabilities: [270] #19
	Capabilities: [2b0] Address Translation Service (ATS)
	Capabilities: [2c0] #13
	Capabilities: [2d0] #1b
	Kernel driver in use: radeon

dmesg, .config, lspci and a picture showing a tty0 with parts of the 
image corrupted by the image of the GDM screen before it was restarted, 
can be found at http://artipc10.vub.ac.be/~frederik/linux-3.7-rc2/

-- 
Frederik Himpe