debugging xorg-x11

[Charles R. Anderson]

I have a FC2 system whose X11 has locked up after sitting on a
screensaver overnight.  I can still get into the system via ssh, but I
cannot vt switch away from the locked up X11.  The X process is taking 
up all the CPU:

USER       PID %CPU %MEM   VSZ  RSS TT       STAT  STARTED     TIME COMMAND
root     23040 97.7  5.2 67488 20248 ?       R     May 22 1-16:02:50 /usr/X11R6/bin/X :0 -audit 0 -auth /var/gdm/:0.Xauth -nolisten tcp vt7

strace shows it in a tight loop:

select(1024, [8], NULL, NULL, {0, 0})   = ? ERESTARTNOHAND (To be restarted)
select(1024, [8], NULL, NULL, {0, 0})   = ? ERESTARTNOHAND (To be restarted)
select(1024, [8], NULL, NULL, {0, 0})   = ? ERESTARTNOHAND (To be restarted)

Xorg.0.log shows this repeating error:

(EE) RADEON(0): GetBuffer timed out, resetting engine...
(EE) RADEON(0): Idle timed out, resetting engine...
(EE) RADEON(0): GetBuffer timed out, resetting engine...
(EE) RADEON(0): Idle timed out, resetting engine...
(EE) RADEON(0): Idle timed out, resetting engine...
(EE) RADEON(0): Idle timed out, resetting engine...
(EE) RADEON(0): Idle timed out, resetting engine...
...

How can I go about debugging this so I can make a meaningful bug
report?  What debuginfo packages and gdb version do I need?

xorg-x11-6.7.0-2 is using radeon driver for this card:

01:00.0 VGA compatible controller: ATI Technologies Inc Radeon RV100 QY [Radeon 7000/VE] (prog-if 00 [VGA])
        Subsystem: ATI Technologies Inc Radeon 7000/Radeon VE
        Flags: bus master, stepping, 66Mhz, medium devsel, latency 32, IRQ 161
        Memory at d0000000 (32-bit, prefetchable)
        I/O ports at d000 [size=256]
        Memory at dd000000 (32-bit, non-prefetchable) [size=64K]
        Capabilities: [58] AGP version 2.0
        Capabilities: [50] Power Management version 2

kernel is 2.6.5-1.358smp.  Chipset:

00:00.0 Host bridge: VIA Technologies, Inc. VT82C693A/694x [Apollo PRO133x] (rev c4)
        Flags: bus master, medium devsel, latency 0
        Memory at d8000000 (32-bit, prefetchable)
        Capabilities: [a0] AGP version 2.0
        Capabilities: [c0] Power Management version 2

00:01.0 PCI bridge: VIA Technologies, Inc. VT82C598/694x [Apollo MVP3/Pro133x AGP] (prog-if 00 [Normal decode])
        Flags: bus master, 66Mhz, medium devsel, latency 0
        Bus: primary=00, secondary=01, subordinate=01, sec-latency=0
        I/O behind bridge: 0000d000-0000dfff
        Memory behind bridge: dc000000-ddffffff
        Prefetchable memory behind bridge: d0000000-d7ffffff
        Expansion ROM at 0000d000 [disabled] [size=4K]
        Capabilities: [80] Power Management version 2

CPUs:

processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 8
model name      : Pentium III (Coppermine)
stepping        : 3
cpu MHz         : 799.919
cache size      : 256 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 2
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 mmx fxsr sse
bogomips        : 1572.86

processor       : 1
vendor_id       : GenuineIntel
cpu family      : 6
model           : 8
model name      : Pentium III (Coppermine)
stepping        : 3
cpu MHz         : 799.919
cache size      : 256 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 2
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 mmx fxsr sse
bogomips        : 1597.44

Thanks.