On Tue, Mar 2, 2010 at 11:07 AM, Arnd Hannemann <hannemann@xxxxxxxxxxxxxxxxxxx> wrote: > Hi, > > I'm currently experimenting with ath5k of kernel 2.6.33 in our > mesh network. We, were previously using madwifi in "ahdemo" mode, > which worked reasonably well. > > At the same time there is no reasonable traffic that justifies this high backlog. > I'm not yet sure, but it may be related to this message in dmesg: > > [ 3681.006797] ath5k phy0: no further txbuf available, dropping packet It's likely. When this happens, we tell mac80211 to stop all of the tx queues -- regardless of which queue stopped -- until the hardware interrupts begin processing tx status descriptors. We re-enable them when there is a certain amount of headroom. > Any idea how to debug this problem further? I would add a printk to where the queues are stopped and re-enabled, and when packets are queued, to determine which queue is using up all of the descriptors. I can put together a patch with the appropriate debug for you if you like, but in a day or two when I'm a bit less busy. By the way, I did notice that if we fail to map DMA buffers we can leak tx descriptors, but this is unlikely to be the cause. -- Bob Copeland %% www.bobcopeland.com -- 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
