Re: NS83820 2.6.0-test5 driver seems unstable on IA64

Andi Kleen
2003-09-19T04:43:15Z

On Thu, Sep 18, 2003 at 09:38:47PM -0700, Grant Grundler wrote:
> On Fri, Sep 19, 2003 at 02:16:29PM +1000, Peter Chubb wrote:
> > The obvious approach of realigning the SKB by 2 bytes seems not to
> > work.
>
> Could you be more detailed about the "obvious approach"?
> ie show the diff of what you changed.
>
> Several other NIC driver "alias" (as davidm describes it) the buffer
> by reserving two bytes at the beginning of the recieve buffer
> where header and payload data are DMAd on inbound traffic.

It is a mixed blessing, because the result is a non cache line
aligned buffer. Some NIC chipsets don't like this because they have
to do a read-modify-write cycle for the first cache line and cannot
burst the full packet.

-Andi