Support for at76c503a

• Getting Sources/Binaries
• Compiling
• Installing
• Starting
• Configure
• Troubleshooting
• Distribution-specific issues
• Getting Help

Getting Sources/Binaries

Chances are that your distribution already contains the driver as a binary module. SuSE 8.2 had the rather old driver version 0.8, SuSE 9.0 comes with version 0.10.

If you want to update, you may either try one of these binaries:

• Tim's RPM-apt repository for RedHat 7.3, 8.0, 9.0 contains an RPM of the driver.

or download the source code: the latest released version from the projects homepage under Latest File Releases or the latest cvs nightly tarball. Unpack them by

tar xzvf filename

Compiling the sources

You need kernel sources matching your running kernel. If you want to compile for a kernel different to the one running, edit the variable KERNEL_VERSION in Makefile

The file /lib/modules/$(KERNEL_VERSION)/build must point to the root directory of your kernel sources.

Your gcc version should match the one used to compile the kernel.

cd into the directory containing Makefile and call

make

Installing the driver

find /lib/modules/`uname -r`/ -name "usbvnet[5r]*" -exec rm {} \;

make install

Starting the device

Plugin your USB device and watch the syslog. If the hotplug package is installed and your USB device's ids are known to the driver, hotplug should load the correct driver. You'll see some lines like

         usbdfu.c: USB Device Firmware Upgrade (DFU) handler v0.11beta4-ac1
         at76c503.c: Generic Atmel at76c503/at76c505 routines v0.11beta4-ac1
         at76c503-rfmd.c: Atmel at76c503 (RFMD) Wireless LAN Driver v0.11beta4-ac1
         ...
         at76c503.c: $Id: at76c503.c,v 1.35 2003/07/30 06:31:51 jal2 Exp $ compiled Sep  2 2003 12:42:49
         at76c503.c: firmware version 1.101.5 #84 (fcs_len 4)
         at76c503.c: device's MAC 00:08:a1:42:9c:d9, regulatory domain ETSI (Europe - (Spain+France) (id 48)
         at76c503.c: registered wlan0
    

If all you get is something like

         usb.c: USB device ... (vend/prod xxx/yyy) is not claimed by any active driver.
    

grep for the USB ids (xxx,yyy) in the source C files. If you find the pair, manually load the corresponding driver (at76c503-rfmd, at76c503-rmfd-acc, at76c503-i3861, at76c503-i3863, at76c505-rfmd,at76c505-rfmd2958), e.g. by

modprobe -v at76c503-rfmd

If this works and you want your system to automatically load the modules, check your hotplug package's configuration.

If you cannot find your USB ids in the source files, try to add it in every of the source files (one after each other) at76c503-rfmd.c, at76c503-rmfd-acc.c, at76c503-i3861.c, at76c503-i3863.c, at76c505-rfmd.c, at76c505-rfmd2958.c. Compile and install and try again. If you've found a working variant, please post device name, USB ids, FCC id, driver name etc. to the user mailing list.

Configure the device

Configure your WLAN device according to your environment with iwconfig, e.g.

iwconfig wlan0 mode ad-hoc essid my_wlan

Do not use WEP or DHCP for the first try, if possible.

Open the network device to activate the device:

        ifconfig wlan0 its_ip_address
    

Try to ping etc. your peer.

In order to automagically start and configure the device please refer to the distribution-specific documentation (hotplug, ifcfg scripts etc.).

Troubleshooting

Compiling

1. compiler error:

       at76c503-rfmd.c:151: error: initializer element is not constant
       at76c503-rfmd.c:151: error: (near initialization for
       `module_usbdfu.reset_delay')
   

   This error is fixed in the cvs tarball.
   
2. compiler error:

       In file included from at76c503.c:86:
       /usr/include/linux/module.h:21: linux/modversions.h: No such file or directory
   

   Check where /lib/modules/`uname -r`/build points to. Must be the root directory of your kernel sources.

Starting

1. modprobe or insmod return unresolved symbols:

       /sbin/insmod /lib/modules/2.4.20-13.9/kernel/drivers/usb/at76c503.o
       Using /lib/modules/2.4.20-13.9/kernel/drivers/usb/at76c503.o
       Symbol version prefix ''
       /lib/modules/2.4.20-13.9/kernel/drivers/usb/at76c503.o: unresolved symbol alloc_skb_Rsmp_60b64813
       /lib/modules/2.4.20-13.9/kernel/drivers/usb/at76c503.o: unresolved symbol usb_alloc_urb_Rsmp_f2742fa6
   

   Check that the kernel sources (including the configuration in .config) match the running kernel. This problem comes up regularly in the at76c503a-user and Atmel-WLAN-USB mailing lists, check their archives (here are two discussions, one for RedHat and another for debian. RedHat keeps the configuration files for its kernel versions in /boot, IMHO you may copy the config file into your kernel root directory, rename it into .config and call

   make oldconfig
   

   in the kernel root directory

2. The driver init messages show up, but you don't see the MAC address line in syslog:

   • If you've used uhci.o or usb-uhci.o as the USB host controller driver, try the other one, e.g. by

            rmmod usb-uhci.o
            modprobe -v uhci.o
     

     and re-plug the device.

   • Enable debugging in usbdfu.o, e.g. by executing

     modprobe usbdfu debug=1
     

     Try again. If the last line in syslog is

     usbdfu.c: scanning unclaimed devices
     

     try to either use uhci.o or try an external hub.
     
   • If you can build your own kernel, build one without USBDEVFS support (CONFIG_USB_DEVICEFS). Try again.
   
   
3. These two lines aren't errors (unless you don't see the device's MAC address below):

   at76c503.c: load_ext_fw_block failed: -32, i = 0
   

   usbdevfs: USBDEVFS_CONTROL failed dev 2 rqt 128 rq 6 len 18 ret -84
   

Configuration

1. iwconfig says

   no wireless extensions for wlan0
   

   Check that the wireless extensions are enabled in your kernel. (CONFIG_NET_RADIO=y). If they are you should have a /proc/net/wireless.

2. Configuration went fine, but you cannot reach the peer (e.g. by ping).

   • Check the mode of your device with iwconfig, you need mode managed to connect to an access point / wireless router; mode ad-hoc to connect to another client
   • Check that you have started the netdevice ("ifconfig wlan0 ip_address").
     
   • Check your firewall configuration. You may try ping6 if available and your kernel is configured for IPv6.
     
   • In case of ad-hoc mode, try to change the start order of both devices.
     

   If you are either running in managed mode or your device is started after the peer, try this:

   • Check if the BSSID of your peer (for access points usually the MAC address, for ad-hoc connections a temporary address starting with 02) is shown by iwconfig. If not, switch on debugging in the module at76c503 and restart the device, e.g. by

           iwpriv wlan0 set_debug 0x180003
           iwconfig wlan0 essid your_essid
           
     

     This should produce more syslog messages describing the parameters of the device, the results of scanning for a peer and the progress of the start sequence. The successful end of the start sequence in managed mode is

           at76c503.c: wlan0: connected to BSSID xx:xx:xx:xx:xx:xx
           
     

     and in ad-hoc mode (second peer):

           at76c503.c: wlan0: state 6 -> 7 (CONNECTED)
           
     

     If you cannot find your peer in the scan results (and it is switched on) and you had to add your USB id yourself into the source code, there is a chance that you've added it into at76c503-rfmd.c, but it must be in at76c503-rfmd-acc.c. You must use the cvs tarball to get that module.
     
   • The driver chooses every peer from the scan result (the BSS table) which matches the configured parameters (mode, WEP on/off, SSID, basic rates). With debug=0x100003 you should see lines like

           at76c503.c: wlan0 BSS table (curr=00000000, new=00000000):
           at76c503.c: 0xf729b1c0: bssid xx:xx:xx:xx:xx:xx channel 12 ssid JOERGS_NW (4A4F455247535F4E57) capa x0011 rates 82 84 0B 16 rssi 34 link 6 noise 0
           at76c503.c: wlan0: state 1 -> 6 (JOINING)
           at76c503.c: wlan0 find_matching_bss: returned f729b1c0
           at76c503.c: wlan0 join addr xx:xx:xx:xx:xx:xx ssid JOERGS_NW type 2 ch 12 timeout 2000
           
     

     In this example the procedure find_matching_bss matched the entry at address 0xf729b1c0 with the parameters and the driver will try to join this BSS. If you see your BSS in the BSS table, but find_matching_bss always returns address 00000000, check your driver parameters (earlier in the syslog). Setting debug=0x180003 shows the reason for skipping certain BSS.
     
   • If your peer device supports 802.11g or 802.11b+, please check that its basic rates (i.e. the mandantory rates) are restricted to the 802.11b rates only (1, 2, 5.5 and 11 MBit/s). The driver will not try to join BSS with other rates marked as basic rates. Have a look into the rates list of BSS table entries in the syslog with debug=0x100003. Basic rates are marked by bit7 set, while the rate itself is coded in the lower seven bits in units of 500 KBit/s. The line

           at76c503.c: 0xf729b1c0: bssid xx:xx:xx:xx:xx:xx channel 12 ssid JOERGS_NW (4A4F455247535F4E57) capa x0011 rates 82 84 0B 16 rssi 34 link 6 noise 0
           
     

     shows a peer with basic rates of 1 and 2 MBit/s, 5.5 and 11MBit/s are optional.
     

   In all configurations:

   • Use a static IP address and no WEP and try again. If WEP is forced by the peer, please check the WEP key. Some configuration tools generate the key from a phrase by a vendor-specific algorithm. iwconfig needs the key in hexdecimal or string format.
     
   • Run a "tcpdump -i wlan0" and try to ping again.
     
   • If the peer is an access point, run a network sniffer on its ethernet port and look for any packets generated by the WLAN.
     
   • Check the routing table and the arp table.
     

Miscellaneous

1. Enabling debug in the driver didn't produce more syslog messages.

   Please check your /etc/syslog.conf and ensure that kern.debug messages are included in the syslog.

Distribution-specific issues

Distribution-specific instructions and help pages are available for Debian/Knoppix (thanks to CE), SuSE, Mandrake 9.1, Mandrake 9.2 (latest two thanks to delboy711).

Getting Help

There are two mailing lists to ask for help, but please search their archives before posting and check if the problem is really related to the driver and not to some distribution specific configuration.

• Berlios user list, its archive
• Atmel-wlan-usb list for both Sourceforge and Berlios driver's issues, its archive

If you're going to post, please include:

• your distribution, kernel version and any kernel patches applied
• driver version
• device name, USB ids
• description of your steps, output of commands etc.
• syslog (including kern.debug, see your /etc/syslog.conf); preferably with debugging switched on for the driver

Jörg Albert