DragonFlyBSD 2.0 RELEASE SCHEDULE / livelocked limit engaged error

[Vincent Stemen]

On Fri, Jul 11, 2008 at 11:40:45AM -0700, Matthew Dillon wrote:
>     The release is scheduled for Sunday 20-July-2008!  We have about a week
>     left!
> 
>     Now is the time for people to list their must-haves and would-likes
>     for the release!  Please use this thread.  I'll start it off:

There is a bug that has been lingering for some time that I would sure
like to see fixed.  We have not been able to run a serial ATA DVDRW
drive on any of our machines.  Any time it is connected, we get
continuous repeating errors like

    intr 10 at 40001/40000hz, livelocked limit engage!
    intr 10 at 19810/20000 hz livelock removed.

We have found a few past postings apparently about this issue that
suggested that the problem might be related to USB.  We have found no
other mention of the problem being related to SATA CDRW/DVDRW drives.
However, it only occurs on our machines when an optical SATA drive is
connected.  SATA *hard* drives work fine and USB works fine otherwise.  We
have tested on two different Intel machines, and an AMD64 machine, with
an add on PCI SiI 3512 SATA150 controller card.  We also tested with the
on board VIA 6420 SATA150 controller on the AMD64 machine.  The problem
exists in all cases.  We have also tested with 3 different SATA CD
drives.

The problem exists on dragonfly 1.10.1-RELEASE and we just tested today
with the latest snapshot ISO image from yesterday (07/12/2008) and it
still exists.

We ran vmstat -i and the number of interrupts coming in from interrupt
10 were massive.  We also tried setting kern.livelock_limit to 80000 but
that did not help.

Let me know if there is any other information that I can provide or
tests that I could run that would be helpful.