Radeon X800 XL not recognized

Binary package hint: xserver-xorg-driver-ati

My video card, a Gigabyte Radeon X800 XL (256M) was not recognized appropriately when I installed Dapper. I got it working (mergedfb, xvideo and 3d included, as tested by watching some videos and playing a game of PlanetPenguin Racer) by lying that its ChipID was 0x554F in xorg.conf, and using the radeon driver directly. The actual relevant lines from lspci and lspci -n:

0000:04:00.0 VGA compatible controller: ATI Technologies Inc R430 [Radeon X800 XL] (PCIe)
0000:04:00.1 Display controller: ATI Technologies Inc R430 [Radeon X800 XL] (PCIe) Secondary

0000:04:00.0 0300: 1002:554d
0000:04:00.1 0380: 1002:556d

glxinfo also complains, but will then succumb to giving a nod for DRI capabilities:

name of display: :0.0
Unknown device ID 554F, please report. Assuming plain R300.
libGL warning: 3D driver claims to not support visual 0x23
libGL warning: 3D driver claims to not support visual 0x24
libGL warning: 3D driver claims to not support visual 0x25
libGL warning: 3D driver claims to not support visual 0x26
libGL warning: 3D driver claims to not support visual 0x27
libGL warning: 3D driver claims to not support visual 0x28
libGL warning: 3D driver claims to not support visual 0x29
libGL warning: 3D driver claims to not support visual 0x2a
libGL warning: 3D driver claims to not support visual 0x2b
libGL warning: 3D driver claims to not support visual 0x2c
libGL warning: 3D driver claims to not support visual 0x2d
libGL warning: 3D driver claims to not support visual 0x2e
libGL warning: 3D driver claims to not support visual 0x2f
libGL warning: 3D driver claims to not support visual 0x30
libGL warning: 3D driver claims to not support visual 0x31
libGL warning: 3D driver claims to not support visual 0x32
*********************************WARN_ONCE*********************************
File r300_state.c function r300Enable line 456
TODO - double side stencil !
***************************************************************************
No ctx->FragmentProgram._Current!!
display: :0 screen: 0
direct rendering: Yes
[...other stuff I think shouldn't be really relevant here, ask if you want it]

I thought I'd report this through Ubuntu, considering that dapper's coming along very soon and I'd like, if possible, for it to recognize my card also, for future reference. Also, I'm not sure if it's maximally healthy for DRI clients to assume that this is "plain R300", as reported by glxinfo above.

Ask away if you need other info; thanks.