Re: Making the NS83820 usable on IA64

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"Jeff" == Jeff Garzik [off-list ref] writes:

Jeff> Peter Chubb wrote:

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With the current NS83820 driver and IP stack implementation, the
IA64 kernel spends 99.9% of its time in the unaligned access trap
handler when the network starts getting busy.  When I raised this
issue before, the idea of realigning the skbuf data in the driver
was scouted; therefore I submit this patch for your approval.  It
makes the driver usable, and doesn't seem to affect anything else.

Jeff> More likely, you need to play around with ns83820.c's
Jeff> skb_reserve() code, in rx_refill():

Unfortunately the dp83820 won't dma to anything other than a 64-bit
aligned packet.  See table 3-2:

  offset  tag		description
   0004h  bufptr	32- or 64- bit pointer to the first fragment
			or buffer.  In transmit descriptors the buffer
			can begin on any byte boundary.  In receive
			descriptors, the buffer must be aligned on
			 a 64-bit boundary.

--
Dr Peter Chubb  http://www.gelato.unsw.edu.au  peterc AT gelato.unsw.edu.au
The technical we do immediately,  the political takes *forever*