On Tue, 2010-09-14 at 22:30 -0700, Ben Greear wrote: > On 09/14/2010 08:03 PM, Jouni Malinen wrote: > > On Mon, Sep 13, 2010 at 04:14:05PM -0700, Ben Greear wrote: > >> This patch aims to decrease channel switching when there is at least one > >> interface associated. This should help multiple station interfaces co-exist > >> on the same hardware, especially in WPA mode. > > > > If I understood the change correctly, it would prevent running full > > scans when in associated state. That does not sound reasonable behavior > > and scanning should not cause an association to be lost. Did I miss > > something or what exactly is this trying to do? > > That's pretty much what I'm trying to do. We had similar code in > our 2.6.31 kernel with ath5k. Imagine getting 50 virtual stations > started with WPA and all of them trying to scan all channels at once! > Most got timeouts, and one scanning would disrupt traffic on the others. > And, the hardware can only associate on a single channel anyway, so getting > scan results for other channels doesn't do a great deal of good. > > With current ath9k, I see DMA timeouts and other nasty things (without > that patch applied) when trying to bring up two VIFs with WPA. > > I think for the multi-VIF scenario, it should scan the single associated > channel by default, but it would be nice to allow full scans on demand. > (I would very much like to work with standard wpa_supplicant, but if hacking it > is the only way, then I can attempt that.) Allowing full scans on demand (ie when userspace requests it) is a must. Even in multi-VIF mode. Dan > > If you want to limit scans a single channel in some special use cases, > > you should be able to do that in user space, too, at least for the > > initial scan before connection. As a future optimization, we should > > somehow be able to merge scan requests from multiple VIFs into a single > > one, i.e., share the results from a single scan to multiple VIFs.. > > Merging would be nice. Maybe store the results in the global hardware/phy > structs and just return that to user-space so long as it's relatively fresh? > > > It would be easier to comment on the changes if you were to inline them > > instead of attaching the file.. > > Sorry about that..I'll inline it next time. It will probably be white-space > damaged, but I can re-send any official patches using git. > > Thanks, > Ben > > -- 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
