On Sat, 20 Aug 2011 15:14:02 -0400, Dennis Nezic wrote: > For that last long while, I have been having strange vague wifi fails > every few days -- my ipw2200 ad-hoc server would suddenly become very > unresponsive -- instead of the usual stable 0.6ms pings, they would > fluctuate wildly from a minimum of about 2ms to 10ms, even though the > connection wasn't being used. More seriously/substantially, iwconfig > would show the "Tx excessive retries" to be steadily increasing -- and > drastically increasing with more usage -- 10-100 retries per second > under heavy usage. I have tried playing with the "Retry limit" "RTS > thr" and "Fragrment thr" values a bit, and with a fixed bitrate, but > they didn't seem to have any significant effect -- the connection > would still inevitably reach this turbulence and ultimately fail, > forcing me to restart it. > > I don't think it's simply a noisy environment, although there are > about 10 other access points around here, none of which shares my > channel 1 at the moment. (There's one on 2, one on 3.) Because that > wouldn't explain why the connection becomes stable and fast after I > restart the wifi interface. > > I'm guessing it's something to do with the driver? So, my ipw2200 pcie wifi card has two wires/antennas, Main and Aux, and (don't ask) my Main one is connected to a good thick antenna (which can sustain rather high ~2MB/s bandwidth), but my Aux one is cut (but can still sustain low ~30KB/s bandwidth). I first noticed something suspicious and coherent when I tried setting the module option antenna=1 (1=Main, 3=Aux, 0=both(default)) ... it seemed more stable -- BUT, it too (especially when being used heavily) would eventually slow down to a crawl/halt, and lead to the incessant increase of "Tx excessive retries". I then tried with the module option antenna=3(Aux), and it immediately was slow/crawling, BUT it would eventually speed up. So, I think either the firmware or the kernel module (which one?) is overriding my antenna option (ie. during high traffic). This shouldn't be allowed. I ended up disconnecting my Aux antenna physically, and my connection (FINALLY!!) seems to have stabilized ... to date, it hasn't slowed down to the crawling (Aux-antenna) speed. There are a few "retry" packets, but they are relatively few and not out of control. (Before, after the first hiccup/slowdown was encountered, they would constantly begin accumulating, unless I restarted the interface.) -- 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
