Am Mittwoch, 17. April 2002 03:14 schrieben Sie:
> Matthias Schuendehuette wrote:
> > I used 'atacontrol' to read the number of tags allowed: it is 31
> > (0x1F). Perhaps Soren could tell me how to force it to, say, 0x10?
> You have to modify the source code in ~line 180 of
> /sys/dev/ata/ata-disk.c.

Well, thanks for the hint. I just have to wait until I get a new 
'current'-world... yesterday it didn't compile and because of an, say, 
'indisposition' of vinum (I changed another slice on a vinum-disk, so 
it dislikes the whole plex :-^ ) I lost my current /usr/obj...

> > Then I tried various combinations of UDMA100/66/33 and wc=0/1 - it
> > nearly doesn't change anything.

BTW: I switched UDMA speed using 'atacontrol'...

> > After the first switch to PIO4, I umounted the filesystem and
> > switched back to UDMA33 for instance - I couldn't even *mount* the
> > filesystem again!
> > [...]
> My hunch, which is why I suggested decreasing the number of
> tags seen by the driver, is that the tagged queues are over
> used, and this locks the disk up. [...]

Yes, I understand this (I for myself had already your 
'off-by-one'-suspicion - it's obvious if one sees the error message) 
and I'll test it ASAP.

What I was wondering yesterday before I fell asleep is that the disk is 
obviously not able to recover from this error - even if the error 
condition is no longer valid due to the switch to PIO-mode. *Any* 
DMA-mode is no longer useable.

I don't know if it's an attribute of these disks or an issue solvable 
by a/the driver. I would expect to be able to do a software reset of 
the drive like with SCSI, but I'm a bit biased against ATA (vs. SCSI) 
because of the opinion/argues of a very knowledgeable guy here in the 
german newsgroup (former core team member ;-), so I wouldn't be 
surprised if that's not possible or not specified.

Ciao/BSD - Matthias

Matthias Schuendehuette <[EMAIL PROTECTED]>, Berlin (Germany)
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