Re: physio split the request.. cannot proceed

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Wed, Dec 25, 2013 at 02:54:19AM +0100, Emmanuel Dreyfus wrote:
> Thor Lancelot Simon <tls%panix.com@localhost> wrote:
> 
> > For what it's worth, I've been *very* busy, but there's not actually much
> > left to do on the maxphys branch 
> 
> I gave it a try, and here is the result on i386:
> /netbsd: mpii0: error 27 loading dmamap
> /netbsd: st0(mpii0:0:3:0): passthrough: adapter inconsistency

I didn't do any work on the mpii driver -- I don't really know
much about it.  I could probably put my hands on suitable hardware.

It looks like the problem is that the driver has a bug -- it is only
using enough bus_dma segments to support a transfer smaller than the
requested 512K, but trying to set up the full transfer anyway.

Looking at the driver I'm a little confused exactly where it's going
wrong but I note a bunch of XXXes around its use of MAXPHYS.

I also notice it has its own minphys() method which _should be_
constraining the size of this transfer (since it should be the minphys
on the scsipi channel) but seemingly is not!  That's also worrisome.

Thor