The following error message is coming up.....

RADEON(0): GPU accel disabled or not working, using shadowfb for KMS

Graphics card is a Radeon 5870, works OK on FGLRX

I have a custom compiled kernel (3.2.9 also 2.6.39.1 has the same error) but the supplied Debian kernel does the same thing.

I have chased through all the docs including the radeon Build howto and as far as I can see it should be working. Help on the next step most apreciated.
I start to a console then run startx, kernel correctly sets console to 1920x1200, the following is part of the output of dmesg

[ 4.582642] [drm] radeon kernel modesetting enabled.
[ 4.582733] radeon 0000:03:00.0: PCI INT A -> GSI 24 (level, low) -> IRQ 24
[ 4.582788] radeon 0000:03:00.0: setting latency timer to 64
[ 4.582904] [drm] initializing kernel modesetting (CYPRESS 0x1002:0x6898).
[ 4.582979] [drm] register mmio base: 0xFBBC0000
[ 4.583027] [drm] register mmio size: 131072
[ 4.583146] ATOM BIOS: GV
[ 4.583206] radeon 0000:03:00.0: VRAM: 1024M 0x0000000000000000 - 0x000000003FFFFFFF (1024M used)
[ 4.583277] radeon 0000:03:00.0: GTT: 512M 0x0000000040000000 - 0x000000005FFFFFFF
[ 4.583347] mtrr: type mismatch for d0000000,10000000 old: write-back new: write-combining
[ 4.583416] [drm] Detected VRAM RAM=1024M, BAR=256M
[ 4.583464] [drm] RAM width 256bits DDR
[ 4.583536] [TTM] Zone kernel: Available graphics memory: 423352 kiB.
[ 4.583588] [TTM] Zone highmem: Available graphics memory: 3109052 kiB.
[ 4.583640] [TTM] Initializing pool allocator.
[ 4.583699] [drm] radeon: 1024M of VRAM memory ready
[ 4.583748] [drm] radeon: 512M of GTT memory ready.
[ 4.583802] [drm] Supports vblank timestamp caching Rev 1 (10.10.2010).
[ 4.583853] [drm] Driver supports precise vblank timestamp query.
[ 4.583929] radeon 0000:03:00.0: irq 77 for MSI/MSI-X
[ 4.583933] radeon 0000:03:00.0: radeon: using MSI.
[ 4.584009] [drm] radeon: irq initialized.
[ 4.584057] [drm] GART: num cpu pages 131072, num gpu pages 131072
[ 4.584514] [drm] Loading CYPRESS Microcode

[ 5.501401] [drm] Internal thermal controller with fan control
[ 5.501482] [drm] radeon: power management initialized
[ 5.636159] [drm] fb mappable at 0xD0141000
[ 5.636208] [drm] vram apper at 0xD0000000
[ 5.636255] [drm] size 9216000
[ 5.636300] [drm] fb depth is 24
[ 5.636345] [drm] pitch is 7680
[ 5.636424] fbcon: radeondrmfb (fb0) is primary device(II) [KMS] Kernel modesetting enabled.
[ 6.064861] Console: switching to colour frame buffer device 240x75
[ 6.070598] fb0: radeondrmfb frame buffer device
[ 6.070599] drm: registered panic notifier
[ 6.070647] [drm] Initialized radeon 2.9.0 20080528 for 0000:03:00.0 on minor 0

part of Xorg.log


(II) [KMS] Kernel modesetting enabled.
(**) RADEON(0): Depth 24, (--) framebuffer bpp 32
(II) RADEON(0): Pixel depth = 24 bits stored in 4 bytes (32 bpp pixmaps)
(==) RADEON(0): Default visual is TrueColor
(==) RADEON(0): RGB weight 888
(II) RADEON(0): Using 8 bits per RGB (8 bit DAC)
(--) RADEON(0): Chipset: "ATI Radeon HD 5800 Series" (ChipID = 0x6898)
(II) RADEON(0): PCIE card detected
(WW) RADEON(0): Color tiling is not yet supported on R600/R700
(II) RADEON(0): KMS Color Tiling: disabled
drmOpenDevice: node name is /dev/dri/card0
drmOpenDevice: open result is 9, (OK)
drmOpenByBusid: Searching for BusID pci:0000:03:00.0
drmOpenDevice: node name is /dev/dri/card0
drmOpenDevice: open result is 9, (OK)
drmOpenByBusid: drmOpenMinor returns 9
drmOpenByBusid: drmGetBusid reports pci:0000:03:00.0


(II) RADEON(0): GPU accel disabled or not working, using shadowfb for KMS