radeondrmkms misbehavior w/AGP on i386?

["John D. Baker" <jdbaker%mylinuxisp.com@localhost>]

In addition to poking at my stash of AGP NVidia cards, I found a couple
of AGP Radeon cards (a 9200 and a 9600SE).

Using a recent i386-8.99.1 build, the radeondrmkmsfb device found them
to its liking--the 9200 is an R200 device and the 9600SE is an R300
device.

Native Xorg liked them as well.  I didn't do any more than just bring
up a basic GUI (fvwm).

Then I noticed something interesting in the dmesg output.  The radeon
driver objected to the minimal AGP window (4MB on the Intel D845EBG2
board) and said a minimum size of 32MB was required and that it was
falling back to PCI mode rather than operate in AGP mode.

I rebooted and changed the AGP window to 32MB as indicated.  The
driver and framebuffer console attached as before.  There was no
longer the message about the AGP window size.

However, in this configuration, starting X sets up the display and then
the machine hangs.  At least the keyboard and mouse are no-longer
responsive.  I did not try SSH and there was no way to arrange for serial
console.

The machine did not even respond to ACPI power-off by the power switch.
As the machine and case had a reset button, that was needed to regain
control.

Returning the AGP window to 4MB, the cards worked with native Xorg
again.

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