On Sun, Oct 01 2006, Tejun Heo wrote: > 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. Don't let that stop you, with good reason it could be changed (or just allowed for some llds). > >>>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. Depends on what the error is. Some drives completely lock up and need a hard power cycle (I've seen this), there's no way the EH can recover that. > >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? I'm guessing that'll be hard. We can scour the .inf files on the drivers that enable NCQ on Windows, that's probably a good set of defaults. -- Jens Axboe - To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
