Re: [RFC] New Qlogic 10Gb Ethernet driver for 2.6.28

[Ron Mercer <ron.mercer@xxxxxxxxxx>]

On Fri, Aug 22, 2008 at 02:43:43PM -0700, David Miller wrote:
> From: Ron Mercer <ron.mercer@xxxxxxxxxx>
> Date: Fri, 22 Aug 2008 10:46:26 -0700
> 
> > On Fri, Aug 22, 2008 at 02:42:52AM -0700, David Miller wrote:
> > > I also notice that this driver does not do:
> > > 
> > > 	skb_reserve(skb, NET_IP_ALIGN);
> > > 
> > > on RX packets to get the IP headers properly 4-byte aligned aligned
> > > after the ethernet header.
> > 
> > The chip currenly has problems with 2-byte aligned receive buffers.
> > It will be fixed in the next turn.
> 
> If the chip cannot handle this, you will need to copy into a properly
> aligned buffer.
> 
> Otherwise some RISC platforms will take unaligned access traps, which
> run extremely slowly, when 32-bit and larger members of the protocol
> headers are read by the networking stack.

I see your point.  I will add the re-alignment but would like to jump
over it for platforms that don't need it.  Is there a list somewhere of
the RISC platforms that take a trap on unaligned accesses?  Or better
yet, a list of those that don't?


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