RT2870 can't find 802.11n routers

Live forum: http://rt2x00.serialmonkey.com/viewtopic.php?t=6102

kcmon

09-11-2010 17:51:38

Kernel 2.6.32.23
Arch ARM Cirrus Logic EP9301

I am attempting to use a USB device with an RT2870F chip on it.
[code2o9tu3hz]Bus 001 Device 004: ID 148f:2870 Ralink Technology, Corp.[/code2o9tu3hz]

The problem that I am experiencing is that when I scan by using iwlist wlan0 scanning, I don't see all the access points. I have two wireless access points within 3 feet of the device. One is called "NG-WIFI" and the other is called "bwifi". NG-WIFI is a Netgear WGT624 v3. The bwifi is a Belkin Share Max F7D3301 v1.

When I load the rt2800usb driver, it detects the USB device properly.
[code2o9tu3hz]
usb 1-3: new full speed USB device using ep93xx-ohci and address 5
usb 1-3: configuration #1 chosen from 1 choice
cfg80211: Calling CRDA to update world regulatory domain
phy0 -> rt2x00_set_chip: Info - Chipset detected - rt: 1600, rf: 0002, rev: 28720202.
phy0: Selected rate control algorithm 'minstrel'
usbcore: registered new interface driver rt2800usb
[/code2o9tu3hz]

I bring the interface up and it loads the proper firmware on the device (version 0.22 downloaded from Ralink).
[code2o9tu3hz]
phy0 -> rt2x00lib_request_firmware: Info - Loading firmware file 'rt2870.bin'.
rt2800usb 1-3:1.0: firmware: requesting rt2870.bin
phy0 -> rt2x00lib_request_firmware: Info - Firmware detected - version: 0.22.
phy0 -> rt2x00mac_conf_tx: Info - Configured TX queue 0 - CWmin: 3, CWmax: 4, Aifs: 2, TXop: 102.
phy0 -> rt2x00mac_conf_tx: Info - Configured TX queue 1 - CWmin: 4, CWmax: 5, Aifs: 2, TXop: 188.
phy0 -> rt2x00mac_conf_tx: Info - Configured TX queue 2 - CWmin: 5, CWmax: 10, Aifs: 3, TXop: 0.
phy0 -> rt2x00mac_conf_tx: Info - Configured TX queue 3 - CWmin: 5, CWmax: 10, Aifs: 7, TXop: 0.
[/code2o9tu3hz]
However when I try to scan for access points, I only see NG-WIFI and not bwifi.
[code2o9tu3hz]
~ # iwlist wlan0 scanning
wlan0 Scan completed :
Cell 01 - Address: 00:14:6C:20:2C:52
Channel:11
Frequency:2.462 GHz (Channel 11)
Quality=70/70 Signal level=15 dBm
Encryption key:on
ESSID:"NG-WIFI"
Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 6 Mb/s
12 Mb/s; 24 Mb/s; 36 Mb/s
Bit Rates:9 Mb/s; 18 Mb/s; 48 Mb/s; 54 Mb/s
Mode:Master
Extra:tsf=000000f0e193e7c4
Extra: Last beacon: 4290ms ago
IE: Unknown: 00074E472D57494649
IE: Unknown: 010882848B968C98B048
IE: Unknown: 03010B
IE: Unknown: 2A0102
IE: Unknown: 32041224606C
IE: IEEE 802.11i/WPA2 Version 1
Group Cipher : CCMP
Pairwise Ciphers (1) : CCMP
Authentication Suites (1) : PSK
Preauthentication Supported
IE: Unknown: DD0900037F0101000EFF7F
IE: Unknown: DD1A00037F030100000000146C202C5202146C202C5264002C010E08
[/code2o9tu3hz]

When I use the Ralink provided driver, bring the interface up, and run a iwlist ra0 scanning, I get the following
[code2o9tu3hz]
~ # iwlist ra0 scanning
ra0 Scan completed :
Cell 01 - Address: 94:44:52:94:0B:5E
Protocol:802.11b/g/n
ESSID:"bwifi"
Mode:Managed
Frequency:2.412 GHz (Channel 1)
Quality:100/100 Signal level:-29 dBm Noise level:-92 dBm
Encryption key:on
Bit Rates:144 Mb/s
IE: WPA Version 1
Group Cipher : CCMP
Pairwise Ciphers (1) : CCMP
Authentication Suites (1) : PSK
IE: IEEE 802.11i/WPA2 Version 1
Group Cipher : CCMP
Pairwise Ciphers (1) : CCMP
Authentication Suites (1) : PSK
IE: Unknown: DD0E0050F204104A0001101044000102
Cell 02 - Address: 00:14:6C:20:2C:52
Protocol:802.11g
ESSID:"NG-WIFI"
Mode:Managed
Frequency:2.462 GHz (Channel 11)
Quality:100/100 Signal level:-36 dBm Noise level:-92 dBm
Encryption key:on
Bit Rates:54 Mb/s
IE: IEEE 802.11i/WPA2 Version 1
Group Cipher : CCMP
Pairwise Ciphers (1) : CCMP
Authentication Suites (1) : PSK
Preauthentication Supported
[/code2o9tu3hz]

I seem to remember a forum post where this issue was described (unable to find 802.11n routers), however there was no resolution. Is this a known issue? If it is, is there a work-around? If you need any additional information, let me know.

IvD

09-11-2010 18:46:55

Please try latest compat-wireless package.

kcmon

10-11-2010 20:04:06

Thanks for the reply. I had wondered if a fix may be located in compat-wireless, however I was having difficulty compiling and installing it on my board. After figuring out a few hurdles, I was able to compile and install compat-wireless on the board.

You were correct, installing compat-wireless fixed the problem with the N routers, however I have found another problem that may or may not be a problem with the driver.

So I load the driver and plug in the wireless device. The driver correctly loads and sees the wireless device. I then bring the interface up. The firmware correctly loads and the interface comes up. So far, everything is perfect. I run wpa_supplicant, and it connects to my bwifi router. So far so good.

However the problem is that when I try to get an IP address via DHCP. It just doesn't work. If I set a static IP address, it works as expected, and a ping test shows no packet loss. However when I try to get an IP address via DHCP, it just sends discovers and that's it.

So I brought up Wireshark on my PC to listen to the packets coming from and to the DHCP server. The packets are extremely random. Sometimes I get a packet for the BOOTP protocol, however Wireshark states that it's malformed. Then other times I will get a proper DHCP Discover packet, which the DHCP server responds with an Offer packet. However the DHCP client never sees it.

Before you think that this is a problem with my DHCP server or client, I have used two rt73usb devices with this board and both have worked with DHCP flawlessly connected to the same router. Not sure if it's a difference between the 802.11g vs 802.11n.

Also for further information, the bwifi router that I am connecting to (described in my previous post) is configured as a standard access point so all router features are disabled including DHCP. The DHCP server is running on our Windows 2003 domain controller.

Any ideas you may have will be appreciated. If you need any additional information, let me know.