tree 72f6a3ba84ef8db0bcbb58c75384e2aa9ccd1c9f
parent 4ec4a67aa100268b4ac5ae32b54843d975969969
author Stephan Gatzka <stephan@gatzka.org> 1317066270 +0200
committer Stefan Richter <stefanr@s5r6.in-berlin.de> 1318172418 +0200

firewire: net: Use posted writes

Change memory region to ohci "middle address space". This effectively
reduces the number of packets by 50%.

[Stefan R.:]  This eliminates 1394 ack packets and improved throughput
by a few percent in some tests with an S400a connection with and without
gap count optimization.  Since firewire-net taxes the AR-req DMA unit of
a FireWire controller much more than firewire-sbp2 (which uses the
middle address space with PCI posted writes too), this commit also
changes a related error printk into a ratelimited one as a precaution.

Side note:  The IPv4-over-1394 drivers of Mac OS X 10.4, Windows XP SP3,
and the Thesycon 1394 bus driver for Windows all use the middle address
space too.

Signed-off-by: Stephan Gatzka <stephan@gatzka.org>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>