Re: Problems associating to AP with rtl8192cu driver

[Larry Finger <Larry.Finger@lwfinger.net>]

On 08/27/2013 03:40 PM, Mark Cave-Ayland wrote:
> On 27/08/13 17:23, Larry Finger wrote:
>
> Hi Larry,
>
>> I just retested and this message was posted from what lsusb says is a
>> "Bus 001 Device 007: ID 7392:7811 Edimax Technology Co., Ltd EW-7811Un
>> 802.11n Wireless Adapter [Realtek RTL8188CUS]" connected to an AP using
>> WPA(1).
>
> I'm actually testing a dongle from a Raspberry Pi that I've been experiencing
> issues with under load with the Realtek-written 8192cu driver. My understanding
> is that it is an OEM RTL8188CUS adapter from here:
> http://thepihut.com/products/usb-wifi-adapter-for-the-raspberry-pi.
>
>> My kernel is 3.11.0-rc6-wl+ from the wireless-testing tree. I have built
>> 3.11-rc7-wl+, but not yet rebooted. Before I boot into that kernel, I
>> will build and test the mainline kernel, but it should not make a
>> difference as the only code differences between wireless-testing and the
>> mainline trees deal with cleaning up some sparse endian issues.
>>
>> What is the make/model of the AP that fails? Is its firmware the latest
>> available? Just to confirm, you are running WPA1 encryption.
>
> It seems to be all of the ones I'm testing :/  Currently that's an old Netgear
> DG834G, a desktop PC running Debian Wheezy/hostapd using a zd1211rw-based WiFi
> dongle, and an O2 Wireless box (rebadged Thomson). The problem seems to be that
> association is difficult, and even when it does associate then the AP appears to
> drop out every minute or so.
>
> The rtl8192cu firmware is that supplied with Debian Wheezy, while the AP
> firmware should also be reasonably up-to-date. Access to all APs is fine using
> an Android phone, the zd1211rw desktop PC and a laptop with an iwlwifi driver.
> The APs are set to advertise both WPA and WPA2 encryption.

The accepted firmware has an md5sum of 943e9b714a926e630b8152d7aad91d2e for 
/lib/firmware/rtlwifi/rtl8192cufw.bin.

>> Do you still have the wireshark file from the failed attempt? If so,
>> could you filter out the traffic from APs and stations other than the
>> units trying to make the connection, and send me (privately) the trimmed
>> file?
>
> Yes - I'm not sure if it's exactly that attempt, but I do have a representative
> wireshark trace of this which I will send to you privately.
>
>> For completeness, I have tested WPA2 with Netgear WNDR3300 and WNDR3400
>> running standard firmware, WPA1 with a Linksys WRT54GL running openWRT
>> Kamikaze fw, and WEP with a Linksys WRT54G V5 running standard fw.
>
> Okay. So perhaps there is something slightly different about this particular
> WiFi dongle...

Neither rtl8192cu nor 8192cu (the vendor driver) work with the 2x2 configuration 
such as found in a TP-Link TL-WN8200ND V1.0. That was reported to Realtek, but I 
have had no response from them.

Larry