Xorg crash on iBook Clamshell G3 and workaround

[Joseph Adams]

On my iBook Clamshell (G3, ATI Rage Mobility M3 AGP 2x (rev 02)), I
couldn't use the ati driver with Fedora 9 because, as Xorg.0.log says,
it can't open the frame buffer device. I successfully used the fbdev
driver, but it's not accelerated.  I later found a workaround to
enable acceleration:

Make sure the Device section has at least these:
        Driver      "ati"
        #the above can also be Driver "r128"
        Option      "UseFBDev" "false"

Make sure the Screen section includes this:
        Option "NoInt10" "true"

The problems are, (1) the ATI driver can't find the frame buffer
device, even though the Xorg "fbdev" driver works fine.  (2) The int10
module crashes if Option "UseFBDev" "false" is set.  However,
disabling int10 fixes the problem. (I guess int10 detection is
unnecessary for iBook, but it should still work).

My xorg.conf now says this:

# Xorg configuration created by pyxf86config

Section "ServerLayout"
        Identifier     "Default Layout"
        Screen      0  "Screen0" 0 0
        InputDevice    "Keyboard0" "CoreKeyboard"
EndSection

#Section "Extensions"
#
#EndSection

Section "InputDevice"
        Identifier  "Keyboard0"
        Driver      "kbd"
        Option      "XkbModel" "pc105"
        Option      "XkbLayout" "us+inet"
EndSection

Section "Device"
        Identifier  "Videocard0"
        Driver      "ati"
        Option      "UseFBDev" "false"
EndSection

Section "Screen"
        Identifier "Screen0"
        Device     "Videocard0"
        Option "NoInt10" "true"
        DefaultDepth     24
        SubSection "Display"
                Viewport   0 0
                Depth     24
#               Modes "800x600"
        EndSubSection
EndSection

I ran glxgears, and it ran for a little while until (3) it locked and
I had to kill glxgears through ssh.  I ran it again, but did not
encounter the same problem the second time.

Has anyone else encountered video regressions on the iBook from F8 to
F9?  The most important issues, as I numbered out above, are:

(1) The ATI driver can't find the frame buffer device, even though the
Xorg "fbdev" driver works fine.
(2) The int10 module crashes if Option "UseFBDev" "false" is set.
Even if int10 isn't needed, it should still not crash.
(3) More sporadic lockups may occur in the future; I haven't tested
with working acceleration long enough to find out.

I ran yum check-update, but I didn't see anything in Fedora 9 for the
kernel or any Xorg drivers.