Re: [Gumstix-users] Building driver modules for Overo

[Vance V. <va...@va...>]

I finally managed to get my Edimax EW-7811Un (rtl8192cu chipset) working
on Overo Earth + Summit running Ubuntu. Thanks to everyone who passed along
helpful suggestions. Here is what I did (some steps may be missing, this is
from memory and reconstructed from "history"): 

 	* Create your root
filesystem using rootstock, with this command (some packages may not be
necessary, feel free to edit):

  sudo rootstock --fqdn overo --login
ubuntu --password temppwd --imagesize 2G --seed
linux-image-omap,gcc,g++,make,build-essential,openssh-server,nano,apt,usbutils,linux-kernel-headers,linux-firmware,wireless-tools,wpasupplicant,zip,linux-source-2.6.35
--components "main universe multiverse" --dist maverick --serial ttyS2  


 	* Install the root fs and kernel as per normal rootstock usage (it's a
tarball with a compressed vmlinuz kernel in / that you need to use mkimage
to prepare uImage for your SD card's FAT directory).
 	* Boot up your
Overo.

	* Rebuild the kernel (the rtl8192cu driver build requires
artifacts that this will produce). You have everything you need to rebuild
because of the rootstock packages you seeded with. To get started: 

 	* cd
to /usr/src and extract linux-source-2.6.35.tar.bz2 (or whatever version
you have).
 	* cd to linux-source.2.6.35
 	* cp /boot/config-2.6.35-22-omap
to ./config
 	* make
 	* make modules
 	* make modules_install
 	* make
install

  	* Install the new kernel. cd to /boot, use mkimage to convert
the compressed vmlinuz-* to uImage, and then copy to your SD card's boot
partition (normally mounted at /media/FAT if you prepared your SD card in
standard Overo fashion).
 	* Reboot your Overo, sudo reboot now
 	*
Download the wifi driver from Edimax website. Unzip and untarball it.

	*
cd to the "driver" directory in the extracted source, and do the following
to build and install the 8192cu module for your Edimax adapter: 

 	* sudo
make -e ARCH=arm
 	* sudo make install

	* Edit /etc/modules and add a new
line with the following, to load the driver at boot: 

 	* 8192cu

	*
Configure wlan0 to start at boot, and use wpa_supplicant to connect to your
secure wifi network: 

 	* Edit /etc/network/interfaces to add these
lines:

  auto wlan0  iface wlan0 inet dhcp  wpa-driver wext  wpa-conf
/etc/wpa_supplicant.conf    

	* 

 	* Create /etc/wpa_supplicant.conf and
give it these contents (update values in quotes to match your network):


network={   ssid="Network Name Here"   scan_ssid=1   key_mgmt=WPA-PSK  
psk="Passphrase Here"   }   

	* 

 	* chmod 0600 /etc/wpa_supplicant.conf
since it contains your wifi passphrase. This will restrict it to root
viewing.

  	* sudo reboot now
 	* You should be online!

 If things didn't
work, you can get some debug info here:   lsusb (make sure your Edimax
device is listed) lsmod (make sure 8192cu is listed as a loaded module)
ifconfig (make sure wlan0 is listed as a network interface) sudo wpa_cli -p
/var/run/wpa_supplicant status (check status of wpa supplicant)   Apologies
for the fragmentary nature of this guide, but it's been a fragmentary
process :) I hope some of these steps help someone else.  Regards,
Vance


On Wed, 23 Feb 2011 18:41:57 -0800, Vance Vagell  wrote:  

Hi folks,


I'm running Ubuntu (Maverick) on an Overo Earth+Summit. I've been trying,
without success, to build a kernel module for a USB wifi adapter (Edimax
EW-7811Un) I'd like to use. 

Is anyone using EW-7811Un (or another
RTL8192-based adapter) on their Overo? I'd love to hear how you got it to
work! In lieu of that... 

I created the kernel and root file system using
rootstock, which automates the process. However, it doesn't seem to include
the kernel source, config, or build output (admittedly, most embedded users
probably don't want these things). 

What this means is I can't build
kernel modules, like the wifi driver I need. 

I've found ways to get the
kernel source or headers installed (certain rootstock options, and even
downloading them pre-packaged from some embedded development sites), but it
seems I need to actually generate a kernel config (yikes), and build the
kernel before I can build modules. 

How have other users built kernel
modules for their Overo systems? In particular: 

* How did you build your
kernel and root FS? Did you use a cross-compiler? Bitbake seems limited to
recipes that won't let me do things like build a root FS that includes
kernel source, headers, etc. 

* Is there an easier way for me to do what
I'm trying to do? Someone off-thread suggested an NDIS wrapper, but that
seems wasteful when there's a perfectly good Linux driver I just need to
compile. 

* Is there some way I can load a comprehensive Ubuntu (or other
modern Linux distrib) onto Overo, short of building it from scratch? I'd
like an environment I can build kernel modules in, without having to build
the kernel. 

I tried to compile the kernel, but got mired in the (hundreds
of?) config questions. I didn't have confidence of what to answer for some
obscurer options. 

Thanks, 

Vance