netdev - Re: [PATCH 1/2] ibm_newemac: Add Support for MAL Interrupt Coalescing

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Message-Id: <1253579943.7103.194.camel@pasglop>
Date:	Tue, 22 Sep 2009 10:39:03 +1000
From:	Benjamin Herrenschmidt <benh@...nel.crashing.org>
To:	prodyut hazarika <prodyuth@...il.com>
Cc:	Prodyut Hazarika <phazarika@...c.com>, netdev@...r.kernel.org,
	Feng Kan <fkan@...c.com>, Loc Ho <lho@...c.com>,
	Victor Gallardo <vgallardo@...c.com>,
	bhutchings@...arflare.com, linuxppc-dev@...ts.ozlabs.org,
	davem@...emloft.net, jwboyer@...ux.vnet.ibm.com,
	lada.podivin@...il.com
Subject: Re: [PATCH 1/2] ibm_newemac: Add Support for MAL Interrupt
 Coalescing

On Mon, 2009-09-21 at 17:28 -0700, prodyut hazarika wrote:
> > BTW. If you guys are ever going to do another change to MAL, please
> > please plase, add the -one- major missing feature that's causing all
> the
> > pain and complication in the current design: Add a per-channel
> interrupt
> > masking option.
> >
> > The lack of ability to mask the interrupt per MAL channel is what
> forces
> > us to create that fake netdev structure in order to share the napi
> > device instance between all the EMACs in the system. This is very
> > inefficient too. We would be able to make things run a lot smoother
> if
> > we could just have a napi instance per EMAC, but for that, we need
> > per-channel interrupt masking.
> >
> 
> I will add a patch for the above as soon as I am done incorporating
> your comments on the MAL coalescing support.
> 
Well... the above is a HW limitation :-) IE. I was suggesting you fix
the HW, but in the case where you already did and the current MAL in
your SoC can indeed mask the interrupt per-channel, then that's great
and we should definitely look into having the driver go back to a more
standard NAPI model on MALs that have that capability.

Cheers,
Ben.

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