| I have tried on many attempts to debug the kernel as below.
| However, I was unsuccessful.  I tried to netboot and test
| the problem, no to avail.  Running the console through a 
| serial port when booted from disk was also not accomplishing
| anything (the amount of data logged simply bogged the OS
| down as it tried to display the messages serially to the
| console port).
|
| I can, however, say that I have had success by purchasing and
| installing a SCSI/NIC board and booting from this device.
| When I boot the system using this SBUS board, I have no more
| problems with the kernel hanging when tagged queuing is 
| enabled.

Is the SCSI on the card the same as the on-board one?

|
| I don't know what else I can do to help debug this problem
| now.  I do, however, have a system running with tagged queuing now
| on my sparc 10 (and it works properly this way on the sparc 5
| as well).

Sun does not use the same controllers for SBus and PCI,
so these machines must be running different drivers.

| > On Wed, Jun 20, 2001 at 07:49:29AM -0500, NetBSD list wrote:
| > > 
| > > Turning off TQING here has indeed resolved the hangs for me on
| > > the Sparc 10.  Thanks.

O.K.  This is a hang.  Can you break into DDB?  If so,
try `ps' and `tr' to see if what's running.  If the machine
is idle (none of the processes have a `>' indicating it is
running), you can try `mach esp' to dump the state of the
device structures.  That should give us some idea what state
the driver is in.

Eduardo