Xorg crashes when using 915resolution on Intel Mobile 915GM/GMS/910GML Express

This laptop has a native resolution of 1280x768 which is not supported by Dapper out of the box (uses 1024x768). In Breezy, 915resolution could be used to set an entry in the table for 1280x768x32 and everything would work fine.

If I set this entry on Dapper and start the X server with a mode of "1024x768" then everything is OK (except for the fact that the screen isn't in its native resolution). If I change the xorg.conf file to have the mode of "1280x768" (having added this mode using 915resolution) then the X server segfaults.

The segfault occurs after logging in at gdm. The gdm login screen comes up fine. It's only after successfully entering username and password that the crash occurs.

Hardware information follows. See attached X server logfile for the crash.

0000:00:00.0 Host bridge: Intel Corporation Mobile 915GM/PM/GMS/910GML Express Processor to DRAM Controller (rev 03)
        Subsystem: ASUSTeK Computer Inc.: Unknown device 1882
        Flags: bus master, fast devsel, latency 0
        Capabilities: [e0] #09 [2109]

0000:00:02.0 VGA compatible controller: Intel Corporation Mobile 915GM/GMS/910GML Express Graphics Controller (rev 03) (prog-if 00 [VGA])
        Subsystem: ASUSTeK Computer Inc.: Unknown device 1882
        Flags: bus master, fast devsel, latency 0, IRQ 10
        Memory at fbe00000 (32-bit, non-prefetchable) [size=512K]
        I/O ports at bc00 [size=8]
        Memory at d0000000 (32-bit, prefetchable) [size=256M]
        Memory at fbdc0000 (32-bit, non-prefetchable) [size=256K]
        Capabilities: [d0] Power Management version 2

0000:00:02.1 Display controller: Intel Corporation Mobile 915GM/GMS/910GML Express Graphics Controller (rev 03)
        Subsystem: ASUSTeK Computer Inc.: Unknown device 1882
        Flags: bus master, fast devsel, latency 0
        Memory at fbe80000 (32-bit, non-prefetchable) [size=512K]
        Capabilities: [d0] Power Management version 2

0000:00:1c.0 PCI bridge: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) PCI Express Port 1 (rev 04) (prog-if 00 [Normal decode])
        Flags: bus master, fast devsel, latency 0
        Bus: primary=00, secondary=01, subordinate=01, sec-latency=0
        I/O behind bridge: 0000c000-0000cfff
        Capabilities: [40] #10 [0141]
        Capabilities: [80] Message Signalled Interrupts: 64bit- Queue=0/0 Enable+
        Capabilities: [90] #0d [0000]
        Capabilities: [a0] Power Management version 2