On Sat, Jul 23, 2011 at 3:35 PM, Christian Lamparter <chunkeey@xxxxxxxxxxxxxx> wrote: > On Saturday 23 July 2011 21:22:35 Harshal Chhaya wrote: >> On Fri, Jul 15, 2011 at 9:22 AM, Christian Lamparter >> <chunkeey@xxxxxxxxxxxxxx> wrote: >> > On Thursday 14 July 2011 21:37:29 Harshal Chhaya wrote: >> >> I am working on an AP design that uses a TI-OMAP3 host processor with >> >> an Atheros AR9170 + AR9101 WLAN chipset. We are currently using >> >> carl9170 version 1.9.2 and carl9170 firmware version 1.9.4. >> > One question: have you considered ath9k_htc? I would certainly recommend >> > it over any ar9170 device. >> >> I was under the impression that AP mode support is better in carl9170 >> than in ath9k_htc. I had considered using AR9271 (which is a more >> recent chipset than the AR9170) but decided against it based on my >> understanding (which is based on the info on the wiki pages). > Interesting... Sujith, can you please take a look at the wiki if ath9k_htc's AP/P2P > infos are still up to date? Thanks for following up on this. I am really interested to know if I should switch to using the AR9271 (or some other similar chipset). > >> If AR9271 (and ath9k_htc) are more stable and preferable to the AR9170 >> w/ carl9170, please let me know. > AR9271 recevied a lot more testing, so it's ought to perform better. > >> Also, to clarify: my application is a wireless network that needs to >> support 60-70 802.11g clients connecting to the AP using WPA2-PEAP. >> All of the clients are battery powered and use the power save >> mechanisms of 802.11. > 60-70 clients is a lot. This would rule out ath9k_htc since the firmwares > only supports 7/8 stations at a time and I think that's a reasonable limit > for any wireless network. Also, with so many stations the hardware crypto > will not have enough space to store all station keys and has to switch to > software de- and encryption. > >> Do you see any issues using AR9170 and carl9170 in this scenario? > Sorry, but I've no data about this scenario. However some time ago > Ben <greearb@xxxxxxxxxxxxxxx> played around 128 stations on a ath9k > network. But I don't know if he tested any USB solutions at that time. I agree - ~8 clients is a reasonable number for most wireless networks. However, I have a specific application where I need to support 60-70 clients on a single AP. I will check with Ben on his experience. Thanks for his contact info. >> Also, I am running openWRT on an TI-OMAP3 processor @ 600 MHz. > Any word about the USB hcd? Does it support sending unaligned data dma, > or is it necessary to align all buffer addresses to a 4-byte boundary? On the specific OMAP3 (the AM3703) in my design, all DMA buffers have to be on a 4-byte boundary. This actually caused some problems for us since we didn't know of this requirement and the openWRT release didn't include this either. We had to merge the TI kernel (the 'arago' project) with the openWRT release to get USB DMA working right. > >> [...] >> The patch definitely helped stabilize the network. Thanks a lot for >> looking into this and providing the patch. > great, but it's a little to late for a tested-by tag. The patch is already on > its way to mainline ;). Sorry - like I said, I started seeing other problems and wanted to track those down. >> However, I still see problems when I enable both WPA2 and power-save >> on the clients. >> >> Here is what I have tried so far: >> >> 30 802.11g clients >> >> open mode + power save - no problems, can send data to all 30 for hrs >> wpa2 + disable power save - no problems, can send data to all 30 for hrs >> wpa2 + enable power save - clients connect but then randomly >> disconnect every few seconds. > Is this with or without the hardware crypto enabled? Usually it's enabled by > default. But in your case I would give it a try to go without one. Just load > the module with: > > nohwcrypt=1 > > this will help to rule out any hw limitations in this regard. Since I don't explicitly disable hw crypto, it is probably enabled by default. I will try disabling hw crypto to see if I can go beyond 30 clients. Thanks again, - Harshal > Regards, > Chr > -- 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
