Some questions about da0 on USB2 (recent bad behaviour)
Andrew Reilly
areilly at bigpond.net.au
Mon Oct 26 21:04:48 UTC 2009
On Sat, Oct 24, 2009 at 07:07:00PM +0000, b. f. wrote:
> >That is: it seems to work fine for some fraction of a minute
> >(doesn't seem to be longer than a minute, anyway), and then
> >stops completely for several minutes (processes reading or
> >writing sit in "D" state in ps) and then starts again, after
> >logging "Request completed with CAM_REQ_CMP_ERR\nRetrying
> >Command".
>
> In the past week or so, Alexander Motin (mav at FreeBSD.org) and Andrew
> Thompson (thompsa at FreeBSD.org) have made a number of related changes
> to cam and usb in the P4 repository, and in 9-CURRENT. Some of these
> may address your problem. I'm not sure when they will be back-ported
> to 8.X. You may wish to try out the latest version of -CURRENT, to
> see if it solves your problem(s); or to contact them.
I've done this, and it seems to have worked. It seems possible
that the bulk throughput (measured by systat while doing a cat
/backup/bigfile >/dev/null) might even have increased a bit,
but maybe not. The big improvement is that the transfer isn't
pausing any more. No more CAM_REQ_CMP_ERR messages.
Thanks b. f. for the suggestion, and thanks Alexander and Andrew
for the fixes!
I haven't run -current for, probably, ten years, and the
occasional messages about lock-order-reversals worry me a bit,
but don't seem to be doing any harm. Should I report them? In
a PR?
Please count this message as a vote for MFC'ing those cam and
usb changes to 8-STABLE.
Cheers,
--
Andrew
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