[Gumstix-users] Overo wifi speed and WPA2 connection issue

[Dirk B. <dir...@go...>]

Due to some private mails and some discussion on the mailling list, 
I'd like to summarize my recent knowledge (status?) regarding subject.

First, wifi speed:

The Overo air wifi module is connected to the OMAP3 processor via MMC 
port 2 in 4 bit configuration. Now, it seems that the OMAP3 MMC driver 
in public omap kernel [1] is polling only. I.e. it does polling data 
transfer and doesn't use interrupts. At the moment the theory is that 
this is the reason for the poor wifi data rates (~100kBytes/s?). We 
did some discussion about fixing this on linux-omap mailing list [2], 
but we haven't found a working patch, yet (?). Looking into the 
archives, the recent status seems to be [3] & [4]. I wasn't able to 
test this due to missing (working) Overo air hardware on my side.

With this, WPA2 connection issue:

I got an Overo air module for testing (thanks again, Steve!). 
Unfortunately, I have some strange WPA2 connection issues with this. 
So I was never able to get the wifi working reliable with this Overo 
air to be able to test the MMC patch(es). See thread [5]. This Overo 
air already has hardly success just getting a successful 'iwlist wlan0 
scan' [6]. Sometimes it never detects my wifi at all, sometimes only 
after 10 or 20 retries.

I have an additional Overo air module. But this has an other HW issue 
and can't test the MMC patch (MMC works only in 1 wire and not 4 wire 
mode). This connects to my WPA2 quite fine using the _same_ SD card 
(having a modified kernel using 1 wire only).

Having this I suspect a HW issue being the reason for the WPA2 issue.

Conclusion:

- People with wifi speed issues might want to test [3]

- People with WPA2 connection issues might want to test how reliable 
[6] is for them. And if wifi network is reliable detected (to exclude 
HW issues) might want to go on reporting results of

wpa_supplicant -Dwext -iwlan0 -c/etc/wpa_supplicant.conf -dddt

to host_ap mailing list.

Best regards

Dirk

[1] 
http://git.kernel.org/?p=linux/kernel/git/tmlind/linux-omap-2.6.git;a=blob;f=drivers/mmc/host/omap_hsmmc.c;h=4b232251890904d2c4014a1c5b8e8fce2b325c07;hb=HEAD

[2] Search

http://marc.info/?l=linux-omap

for 'SDIO IRQ' or 'Behme'

[3] http://marc.info/?l=linux-omap&m=126140067103975&w=2

[4] http://marc.info/?l=linux-omap&m=126141430025116&w=2

[5] http://lists.shmoo.com/pipermail/hostap/2009-November/020554.html

[6] http://gumstix.net/wiki/index.php?title=Overo_Wifi#Test