Re: cvs commit: src/sys/dev/disk/sbp sbp.c

[Hidetoshi Shimokawa <simokawa@xxxxxxxxxxxxxxxxxxx>]

At Tue, 13 Jan 2004 09:32:12 -0800 (PST),
Joerg Sonnenberger wrote:
> 
> joerg       2004/01/13 09:32:12 PST
> 
> DragonFly src repository
> 
>   Modified files:
>     sys/dev/disk/sbp     sbp.c 
>   Log:
>   Add hw.firewire.sbp.tags to control tagging for SBP devices. The default
>   behaviour was changed to disable tagged command queues, which is safer since
>   not all firewire chips support TCQ.

As the nature of SBP-2, all commands are tagged and all target should
support tagged queuing. I know some drives does't work well
with command queue longer than 1, though. I digged the problem before and
found that this is not because the target drive doesn't support the
tagged queuing but it sometimes respones with bogus command chain
status and this confuses the initiater(sbp.c).

You can limit the queue length for such devices by:
# camcontrol X:X:X tags -N 1

I have installed DFB in one of my machine. I'd like to sync the
firewire drivers in DFB with those in recent FreeBSD's tree.

I'm interested in SSI(Single System Image) of DFB and
I think the FireWire bus can be a efficient trasport layer for it.

/\ Hidetoshi Shimokawa
\/  simokawa@xxxxxxxxxxxxxxxxxxx
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