Re: Another twist on WRITE_DMA issues <- ProblemFound

At 9:31 PM -0500 12/2/04, Garance A Drosihn wrote:
>
>I have now switched from that Western Digital drive to a Seagate
>Barracuda 7200.7 120-gig (ST3120026AS).  The drive seems to be
>working fairly well, but now I sometimes see some combination
>like the following three lines:
>
>Dec  2 20:29:50 kernel: Interrupt storm detected on
>                         "irq20: atapci0"; throttling interrupt source
>Dec  2 20:29:54 kernel: ad4: TIMEOUT - WRITE_DMA retrying
>                         (2 retries left) LBA=20627679
>Dec  2 20:29:54 kernel: ad4: FAILURE - WRITE_DMA timed out
>
>Where atapci0: <VIA 6420 SATA150 controller>
>And
>ad4: 114473MB <ST3120026AS/3.56> [232581/16/63] at ata2-master SATA150
>
>This does not come up often, and it usually doesn't cause any
>noticeable problem.  As it luck would have it, the one time it has
>caused problems is during installworlds. ...

It has caused problems on many other occasions, too.

But in any case, it looks like this set of problems are my own
fault.  Earlier, I spent about two months trying to solve problems
on this PC which (it turned out) were due to the SiL SATA controller
combined with the western-digital drive.

Just before I realized that SATA controller was the problem, I had
added:
       hw.ata.ata_dma=0
to /boot/loader.conf.local, because someone else had suggested that
it *might* help with my earlier WRITE_DMA problems.  At that time,
the setting seemed to make no difference.  But now that I am using
a good SATA controller *and* I have switched to the "real-SATA" hard
drive from Seagate, the above setting seems to *cause* problems.

I removed that setting, rebooted, and I have now done a complete
buildworld/installworld cycle without seeing a single "interrupt
storm" or a single WRITE_DMA error.  While the setting was still
there, I would always see at least a few of those warning messages
(and sometimes end up with a system panic).  So, my hope is that
this has finally solved the last of my problems with this machine.

-- 
Garance Alistair Drosehn            =   gad_at_gilead.netel.rpi.edu
Senior Systems Programmer           or  gad_at_freebsd.org
Rensselaer Polytechnic Institute    or  drosih_at_rpi.edu