Ric Wheeler wrote:
Jens Axboe wrote:
On Sat, Sep 30 2006, Alan Cox wrote:
Ar Sad, 2006-09-30 am 20:04 +0200, ysgrifennodd Jens Axboe:
On Sat, Sep 30 2006, Tejun Heo wrote:
Turn off NCQ if queue depth is adjusted to 1.
I had thought of that too but discarded it - it would be nicer to have
an independent way of turning off NCQ. Say you are debugging a weird
FIS
issue, NCQ depth 1 is still a different beast to non-NCQ. I see Jeff
already applied the patches, but just thought I'd voice my opinion.
Yeah, I was putting off this patch for the same reason. 0 depth would
have been nice but SCSI midlayer filters such input and libata still
doesn't have its own sysfs tree. So, this was the middle ground.
I've got a blacklist for NCQ in my work tree but really we need the
vendors to help fill it. So far it has some raptors in it but I am sure
there are more, and I am sure there are cases we should be advising
newer firmware or just tweaking our queue sizes etc.
Lots of the older Maxtors are pretty crappy for NCQ, so those too. Queue
size tweaks fixed them for me (as low as 4, and I can't say for sure if
it fixes all crashes).
I'm gonna update EH such that NCQ is turned off after certain number of
errors. That should at least eventually make the machine usable in such
cases, but we definitely need NCQ blacklist.
We have to be careful with the blacklisting - specifically, drive model
is often less critical than the version of the firmware (which gets
updated as people work drives through qualification, etc).
Updating drive firmware for end users is pretty rare (and almost all
tools are still DOS based ;-)).
Certain drives should default to non-NCQ (based on model), but we should
be able to enable it if the firmware supports it.
Most of the newest drives are fine, but we will still need something
like Tejun's fix to be able to turn it off for the odd cases that show
up in certain odd applications, etc.
Ric, can you press harddisk vendors hard enough such that those model
and revision numbers squeeze out of them?
Thanks.
--
tejun
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