Radeon 7500 and Apple 22" cinema display

[Gavin Hemphill]

Well, I've read all the archived messages on this and tried the 
suggested solutions to no avail.  Machine: Quicksilver 733, Apple ATI 
Radeon 7500 agp card, Apple Cinema 22" display with Apple Display 
connector.  Both OS 9.2.2 and 10.1.5 work fine with the card.   running 
YDL 2.3 (with the YDL 2.4.19-4a kernel and a few recent benh kernels - 
today's bk pull fails during building the modules but earlier ones boot 
fine).  The results are the same.  If I boot with the video=radeon:dfp 
argument dmesg shows the card, but insists there is no monitor connected 
(see below).  I'd really like to know how to get YDL to work with this 
combo.  Is there some magic in OF required to get the card to recognize 
that there is a display connected?  Note: this machine had a Nvidia 
GeForce2-MX in it earlier but I managed to trade that for the Radeon in 
the hope that I could get a working X configuration.

relevant dmesg output:

dmesg output with video=radeon:dfp

radeonfb: ref_clk=2700, ref_div=12, xclk=20025 from OF
radeon_get_moninfo: bios 4 scratch = 0
Console: switching to colour frame buffer device 80x25
radeonfb: ATI Radeon 7500 QW  DDR SGRAM 32 MB
radeonfb: DVI port no monitor connected
radeonfb: CRT port no monitor connected
no framebuffer address found for 
/pci@f0000000/ATY,BlueStoneParent@10/ATY,BlueStone_B

dmesg output with offb (i.e. novideo option)

Using unsupported 1600x1024 ATY,BlueStone_A at 9c008000, depth=8, pitch=1792
Console: switching to colour frame buffer device 200x64
fb0: Open Firmware frame buffer device on 
/pci@f0000000/ATY,BlueStoneParent@10/ATY,BlueStone_A
no framebuffer address found for 
/pci@f0000000/ATY,BlueStoneParent@10/ATY,BlueStone_B