2012/8/22 Hauke Mehrtens <hauke@xxxxxxxxxx>: > On 07/18/2012 01:56 PM, Bastian Bittorf wrote: >> hi devs! >> >> yesterday we had a breaktrough debugging b43 in our hackspace maschinenraum/m18[1,2] >> at weimar.freifunk.net[3,4] - since a long time our darling wrt54g suffers from a >> hanging wifi and bad performance[5], but the workaround is easy: now it's up to >> you to fix the rootcause. >> >> our testsetup, where we could _reproduce_ reliably a stopping TX is like this: >> >> laptop ---lan--- "A"-wrt54g/adhoc ~~~ air ~~~ "B"-anyrouter/adhoc >> >> now make a testdownload with the laptop from B. >> wireless will stop working after ~10 seconds. >> >> wifi up will reanimate and our freifunk-cron.minutely-check >> will do this automagically. (read further, this is not the solution) >> >> we tried to limit the rateset to e.g. lower rates, but this does NOT change >> the behaviour. what works is: define a rateset on BOTH router which makes >> it impossible to change the band, e.g.: >> >> iw dev $WIFIDEV set bitrates legacy-2.4 1 2 5.5 11 >> OR >> iw dev $WIFIDEV set bitrates legacy-2.4 6 9 12 18 24 36 48 54 >> >> now we had a great performance, 10 Gigabytes of wireless transfer, >> no stopping TX anymore and an empty box of beer. three things to do now: >> >> 1) why does a band change (can be seen through minstrel) is a problem? >> >> 2) we have to make in config-option to force a band, or a rateset: >> e.g. uci set wireless.radio0.hwmode=11g >> e.g. uci set wireless.radio0.bitrates='6 9 12 18 24 36 48 54' >> >> 3) spread to word: >> there is a great frustration in the community about b43, >> but the old drivers _have_ to die, it's about time - really. >> >> thanks for your work, >> bye storchi, andi, bastian + m18 crew >> >> [1] http://blog.maschinenraum.tk/ >> [2] http://blog.maschinenraum.tk/2012/07/15/bitcoin-vending-machine-exchange-euro-coins-for-bitcoin-wallets/ >> [3] http://wireless.subsignal.org >> [4] http://wireless.subsignal.org/index.php?title=Main_Page_en >> [5] https://dev.openwrt.org/ticket/7552 > > I tried this on some of my devices (BCM4318 G-PHY and BCM4322 N-PHY) and > it is easily reproducible on all tested devices when restricting the > rates to 11 and 12 MBit/s. > > I have the Broadcom device working as an Access point (on a MIPS SoC) > and a Laptop with an Intel Wifi device is connected to it. I generated > the traffic with iperf. If the Access Points sends the traffic the > problem occurs, if it is just receiving there is not problem. > > After the problem occurred b43_generate_txhdr is called rarely ( every > ~10 seconds) and I am not able to stay connected or connect to the > network any more. I am not familiar with the internal flow in b43 or > mac80211 could someone give me a hint where to look. > > I can not see any special changes between CCK and OFDM rates before it > goes down there are many changes without a problem before it goes down. > > Currently I do not have a Broadcom wifi card running in a x86 device > just mips devices could someone try to reproduce the problem on a x86 > device. > > I added the b43 mailing list and Rafał. Does your kernel include commit bad6919469662b7c92bc6353642aaaa777b36bac Author: francesco.gringoli@xxxxxxxxxxxx <francesco.gringoli@xxxxxxxxxxxx> Date: Fri Dec 16 18:34:56 2011 +0100 b43: avoid packet losses in the dma worker code. ? I have a lot of things on my TODO list, including that. Right now I just want to focus on BCM4706 support, which slowly moves into mainline. -- Rafał -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
