With a new version of Ubuntu (using 9.04), I thought I might have more luck. With this version, direct rendering works according to $ grep glxinfo | rendering. I booted up an old version of lxdream, accidentally, and was able see some output. It was too slow to work properly, however, so I decided to try the newest version of lxdream as well. With version 0.9, the game doesn't play.

I've accepted that I won't be able to play DC games on my laptop, but I thought it might be useful if I posted my core dump. If this means anything to you, let me know:

root@LucidLinux:/home/john/Programs/Dreamcast# ./lxdream
20:50:08 A0000000 WARN Unable to load file 'bios/IP.BIN': No such file or directory
20:50:09 8C010040 WARN Attempted write to unknown P4 region: FFFFFFFC

--
KallistiOS ##version##: Thu May 15 15:51:34 PDT 2008
root@anothrcomputer:/home/john/dc/kos
thd: pre-emption enabled, HZ=100
20:50:09 8C034D4E WARN ARM Halted: BRANCH to invalid address FFFFFFE8 at 00000004
maple: active drivers:
Dreameye (Camera): Camera
Sound Input Peripheral: Microphone
PuruPuru (Vibration) Pack: JumpPack
VMU Driver: Clock, LCD, MemoryCard
Mouse Driver: Mouse
Keyboard Driver: Keyboard
Controller Driver: Controller
DMA Buffer at ac14bce0
vid_set_mode: 640x480IL NTSC
fs_romdisk: mounting image at 0x8c05b020 at /rd
dc-load console support enabled
maple: attached devices:
A0: Dreamcast Controller (01000000: Controller)
pvr: enabling vertical scaling for non-VGA
--- Aborting with signal 11 ---
[Thread debugging using libthread_db enabled]
[New Thread 0xb7357720 (LWP 7599)]
0xb8036430 in __kernel_vsyscall ()
#0 0xb8036430 in __kernel_vsyscall ()
#1 0xb76d02a3 in waitpid () from /lib/tls/i686/cmov/libc.so.6
#2 0xb766a57b in ?? () from /lib/tls/i686/cmov/libc.so.6
#3 0x08080118 in report_crash (signo=11, info=0xbfc50f9c, ptr=0xbfc5101c) at util.c:47
#4 <signal handler called>
#5 0xb52b26c0 in intelFinish () from /usr/lib/dri/i965_dri.so
#6 0xb530ee11 in _mesa_Finish () from /usr/lib/dri/i965_dri.so
#7 0x080825df in gl_fbo_display_render_buffer (buffer=0xa7db068) at drivers/gl_fbo.c:322
#8 0x08072dce in pvr2_display_frame () at pvr2/pvr2.c:456
#9 0x0807302c in pvr2_scanline_callback (eventid=4) at pvr2/pvr2.c:124
#10 0x0805a6a2 in event_execute () at eventq.c:215
#11 0x0805b0dd in sh4_sleep_run_slice (nanosecs=1000000) at sh4/sh4.c:510
#12 0x0805b494 in sh4_run_slice (nanosecs=1000000) at sh4/sh4.c:148
#13 0x0805a09b in dreamcast_run () at dreamcast.c:209
#14 0xb78f3b54 in g_cclosure_marshal_VOID__VOID () from /usr/lib/libgobject-2.0.so.0
#15 0xb78e5cab in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#16 0xb78fd3a9 in ?? () from /usr/lib/libgobject-2.0.so.0
#17 0xb78fea1b in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#18 0xb78feec6 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#19 0xb7c90515 in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#20 0xb7c926a5 in gtk_action_activate () from /usr/lib/libgtk-x11-2.0.so.0
#21 0xb7e6655f in ?? () from /usr/lib/libgtk-x11-2.0.so.0
---Type <return> to continue, or q <return> to quit---
#22 0xb78f3b54 in g_cclosure_marshal_VOID__VOID () from /usr/lib/libgobject-2.0.so.0
#23 0xb78e5cab in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#24 0xb78fd3a9 in ?? () from /usr/lib/libgobject-2.0.so.0
#25 0xb78fea1b in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#26 0xb78feec6 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#27 0xb7cace5a in gtk_button_clicked () from /usr/lib/libgtk-x11-2.0.so.0
#28 0xb7cae968 in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#29 0xb78f3b54 in g_cclosure_marshal_VOID__VOID () from /usr/lib/libgobject-2.0.so.0
#30 0xb78e4409 in ?? () from /usr/lib/libgobject-2.0.so.0
#31 0xb78e5cab in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#32 0xb78fcc40 in ?? () from /usr/lib/libgobject-2.0.so.0
#33 0xb78fea1b in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#34 0xb78feec6 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#35 0xb7cacefa in gtk_button_released () from /usr/lib/libgtk-x11-2.0.so.0
#36 0xb7cad124 in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#37 0xb7d7e1c2 in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#38 0xb78e4409 in ?? () from /usr/lib/libgobject-2.0.so.0
#39 0xb78e5cab in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#40 0xb78fd067 in ?? () from /usr/lib/libgobject-2.0.so.0
#41 0xb78fe8df in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#42 0xb78feec6 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#43 0xb7eb282e in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#44 0xb7d75cfa in gtk_propagate_event () from /usr/lib/libgtk-x11-2.0.so.0
---Type <return> to continue, or q <return> to quit---
#45 0xb7d77297 in gtk_main_do_event () from /usr/lib/libgtk-x11-2.0.so.0
#46 0xb7be47ca in ?? () from /usr/lib/libgdk-x11-2.0.so.0
#47 0xb7857af8 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#48 0xb785b05b in ?? () from /usr/lib/libglib-2.0.so.0
#49 0xb785b52a in g_main_loop_run () from /usr/lib/libglib-2.0.so.0
#50 0xb7d77799 in gtk_main () from /usr/lib/libgtk-x11-2.0.so.0
#51 0x080509a8 in main (argc=1, argv=0xbfc524f4) at main.c:248
Aborted (core dumped)