Hi,
Using scsipi_base.c revision 1.135 my AlphaServer 4100 locks up on boot.
I can still get to ddb, it's stuck in scsipi. If I back out to 1.134 it
works again.

cd0 at scsibus0 target 5 lun 0: <DEC, RRD46   (C) DEC, 1337> cdrom removable
cd0: sync (100.00ns offset 8), 8-bit (10.000MB/s) transfers

Here it locks up. Normally it would probe sd0 at scsibus1
at this point. Pressed the halt button to get ddb:

panic: user requested console halt
Stopped at      netbsd:cpu_Debugger+0x4:        ret     zero,(ra)
db> bt
cpu_Debugger() at netbsd:cpu_Debugger+0x4
panic() at netbsd:panic+0x1e8
console_restart() at netbsd:console_restart+0x78
XentRestart() at netbsd:XentRestart+0x90
--- console restart (from ipl 0) ---
idle() at netbsd:idle+0x30
mi_switch() at netbsd:mi_switch+0x1c0
ltsleep() at netbsd:ltsleep+0x540
scsipi_execute_xs() at netbsd:scsipi_execute_xs+0x320
scsipi_command() at netbsd:scsipi_command+0xc0
scsipi_inquire() at netbsd:scsipi_inquire+0xa4
scsi_probe_device() at netbsd:scsi_probe_device+0x22c
scsi_probe_bus() at netbsd:scsi_probe_bus+0x184
scsibus_config() at netbsd:scsibus_config+0xac
scsipi_completion_thread() at netbsd:scsipi_completion_thread+0x308
exception_return() at netbsd:exception_return
--- root of call graph ---
db>

-Tobias