radeon and flat panels

[Rob Pfile]

About 1.5 years ago i got an SGI 1600SW and multilink adaptor. the
multilink is very finicky on it's DVI input -- it pretty much only
recognizes 1600x1024 at 60Hz. 

somehow i guess the radeon driver does not properly pick up my open
firmware settings on boot, and i think it tries to switch to
640x480-60, giving me a blank screen (but at least the multilink does
display a banner saying "unsupported mode." I never really figured out
why the OF settings were getting clobbered, but i did find a
workaround. after much pain searching around on the web, i found the
XFree86 timings for this display and converted it to an /etc/fb.modes
style entry. i added this to the end of /etc/fb.modes:

mode "1600x1024-60"
    geometry 1600 1024 1600 1024 8
    timings 9259 64 16 25 16 40 3
endmode

and this to /etc/rc.sysinit right at the beginning:

/usr/sbin/fbset -a 1600x1024-60

that sets all the virtual consoles to the 1600x1024 @ 60Hz mode soon
after the machine has begun booting, and the display comes up.


another problem was that until i added this line of code:

drivers/video/radeonfb.c (v0.1.5) line 853:
                /* chipset */
                switch (pdev->device) {
                        case PCI_DEVICE_ID_RADEON_QD:
                                strcpy(rinfo->name, "Radeon QD ");
                                /* pfile: make dvi output work */
                                rinfo->hasCRTC2 = 1;
                                break;

the DVI output on my particular card never worked at all. this hack
is probably not correct and may have something to do with the driver
not getting the OF settings, but what can i say, it worked.

here is what i see in dmesg:

PCI: Enabling device 00:10.0 (0086 -> 0087)
radeonfb: ref_clk=2700, ref_div=67, xclk=16615 from OF
radeon_get_moninfo: bios 4 scratch = 0
Console: switching to colour frame buffer device 80x30
radeonfb: ATI Radeon QD  DDR SGRAM 32 MB
radeonfb: DVI port no monitor connected
radeonfb: CRT port no monitor connected

finally, i've found only very recently that the radeon accelerated
video driver in XFree86 works great against my card. i simply took the
/etc/X11/XF86Config-4 file that came with the XFree86 RPMs distributed
from YDL 2.3, and changed the Driver line in the "Device" section to
"ati".

for reference here is my /etc/yaboot.conf entry:

image=/boot/vmlinux-2.4.20-pre5-ben0
        label=2420
        root=/dev/hda11
        append="video=radeon idebus=66"
        read-only

i havent gotten DRI to work but i suspect at 1600x1024 there isnt
enough framebuffer memory (the card only has 32MB)

and on to MOL: molvconfig tries to switch to 640x480-60 as well and so
i get the blank screen while it's trying to ask me about
resolutions. but i did manage to get thru it blindly, and i can post
my mol video timings file if anyone is interested. (i dont have it
handy right now since i recently reinstalled everything from scratch
onto a new disk and i forgot to copy that over.)

hope all of this helps someone. i'm guessing it will apply to the
apple 22" cinema display because the display timings shipped with
XF86Config-4 in YDL2.3 seem to work fine against my display.

rob