Re: if_bnx issues

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Fri, Feb 06, 2015 at 09:44:34PM +0000, David Laight wrote:
> On Thu, Feb 05, 2015 at 06:24:02PM -0500, Greg Troxel wrote:
> > 
> > I am trying to integrate a number of fixes for if_bnx back to netbsd
> > proper.  These are mostly about issues that manifest under unreasonable
> > load leading to mbuf exhaustion.  I would like some review on these.
> > 
> > This fix is due to Beverly Schwartz.
> > 
> > The issue is failing to get new hw_cons value from the hardware due to a
> > missing dmamap_sync.  This patch did fix the issue (on i386) and systems
> > with it are stable, but I'm not 100% certain the dmamap_sync is entirely
> > right.
> 
> I don't know what bus_dmamap_sync() is supposed to sync, nor
> what it actually does on i386/amd64, but I suspect it doesn't do
> anything significant.

If bounce buffers are used, in copies data between the bounce and
the user-supplied buffer.

It also does x86_mfence() or x86_lfence(), depending on the
operation.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--