Subject: Re: [PATCH] b43: Increase number of RX DMA slots

From: Bastian Bittorf <[email-masked]>
Date: Tue, 19 Feb 2013 21:01:31 +0100

* Larry Finger <[email-masked]> [18.02.2013 21:17]:

> (14e4:4315) units. I think the firmware and DMA can handle it. After
> all, all the TX rings have 256 slots. There is, however, a question
> of the memory. TX only acquires the buffers when needed, but RX has
> to get them in advance, thus 256 slots there will waste a lot of
> memory.

I did some testing with 256 slots and the
"b43-workaround-rx-fifo-overflow.patch" on a very slow board,
an i'am sure, that 128 slots are not enough. kernel-log is here:

http://intercity-vpn.de/files/openwrt/b43test.dmesg.txt

this was a normal download (100mb @ 1 megabyte/s), but if you
do some udp-magic (netperf) you run soon into trouble.

thanks for your work!

bye, bastian / wireless.subsignal.org / weimarnetz e.V.