3. Configuring the Kernel
3.1. Requirements
Some obvious things are required, such as a computer,
USB ports, Handspring Visor (with USB cradle).
You should also know how to compile and install programs
and the kernel. If you do not, you have a few options:
learn, get your resident expert to help you, or get a distro
with everything prepared for you.
If you don't have a USB controller for your computer, then
you need to either buy the serial cradle for the Visor
(but you wont need this document), or buy a USB-capable
device for your computer (ie. add-on card or a new
motherboard).
3.2. Kernel Version
The linux kernel version v2.4 was the first to have USB support. You can get the latest v2.4 kernel from:
ftp://ftp.kernel.org/pub/linux/kernel/v2.4/.
The USB code has been backported to the v2.2 kernel, starting
at version v2.2.18. If you must, you should probably be
able to follow the same instructions with the latest v2.2 kernel
Now would be a good time to download the latest kernel, and
configure things to your desire. The following has the
instructions you need to configure USB.
If you have already have compiled and installed the kernel,
you should not need to reboot! All we need to do is
to compile and install the appropriate modules, and we
will be all set.
3.3. USB Controller Type
The first thing to do is o determine which type of USB
host controller you have. The USB host controller is the
hardware in your computer which handles USB input/output.
Motherboards based on Intel chipsets, are
typically UHCI controllers. Most addon cards are OHCI
controllers. You can determine the type of USB hardware
available by using, as root, the following command:
If you see an entry like:
USB Controller: ......
Flags: .....
I/O ports at .... |
Then you have a UHCI based controller. If you see an entry like:
USB Controller: .....
Flags: ....
Memory at ..... |
Then you have a OHCI based controller. You could
refer to http://www.linux-usb.org
for further details. The kernel documentation
/usr/src/linux/Documentation/usb/usb.txt may
also be helpful in determining which type of controller
you have.
3.4. Configure/Build Kernel
Now we need to configure, and make your kernel. During
configuration, make sure you enable the following entries.
You may either compile them directly into your kernel,
or as modules. It is highly recommended that you compile
them as modules. If you compile them directly in, you will
need to reboot.
USB support (CONFIG_USB)
The preliminary USB Device Filesystem
(CONFIG_USB_DEVICEFS)
The appropriate controller - UHCI, or OHCI
(CONFIG_USB_UHCI, or
CONFIG_USB_OHCI)
USB Serial Converter support
(CONFIG_USB_SERIAL)
USB Handspring Visor Driver
(CONFIG_USB_SERIAL_VISOR)
(serial converter's sub-option)
There are two UHCI drivers. You do not want the "UHCI
Alternate (JE)" driver. This driver does not yet support
all the USB features which the Visor uses. Thus, you will be
unable to sync using this driver. If you are unable to
see the original driver, ensure that the UHCI-JE driver
is NOT selected, you should then see the option for both
drivers.
Here, you should decide if you would like to include
Hotplug support. With Hotplug support, you are able
to auto-magically sync your visor by only pressing the
Hotsync button. Please see the
hotplug section, and
especially the Hotplug Kernel
Config, before choosing this route.
Compile and install as required. Don't forget to run
lilo. If you are installing a new kernel image, do not
reboot yet.
3.5. usbdevfs
usbdevfs puts information about your
USB bus into the
/proc
directory tree. Its a good thing, and can be especially
useful for debugging. You can enable it by adding the
following line into your /etc/fstab.
none /proc/bus/usb usbdevfs defaults 0 0 |
If you installed a new kernel image, you could reboot
from this point on. Remember, if you are just adding the
USB info as modules, you do not need to reboot.
3.6. Making /dev Entries
If your linux distro does not come with USB Visor support,
or if you are NOT using devfs (not
the same thing as usbdevfs), you will need
to make the USB tty devices.
If you are using devfs, these devices are
automagically created under
/dev/usb/tts/{0,1,...}; so you can skip
ahead to using the modules
If you are not using devfs, you can create
the devices by executing these commands, as root:
mknod /dev/ttyUSB0 c 188 0
mknod /dev/ttyUSB1 c 188 1
mknod /dev/ttyUSB2 c 188 2
mknod /dev/ttyUSB3 c 188 3
etc...
chmod 666 /dev/ttyUSB*
|
You are able to have up to 255
connections/ports/devices, but unless you have more than
one USB serial device, you'll probably only need the first few.
The chmod is to allow users to be able to access the Visor
device. It is the opinion of the author of this document
that this should be safe for a personal computer. Multiuser
computers may want to look into the security for this
(please let me know).
When a Visor connects, there are two "ports" opened. (For
most people, this will be /dev/ttyUSB0,
and /dev/ttyUSB1). The first port
(zero), is a generic connection. The second
port is the hotsync port. This feature allows for future
developments; for example, to export a filesystem from the
Visor. A useful thing to do is to create a link to the
hotsync port so that synchronization software will use the
appropriate device be default. You can do this by:
cd /dev
ln -s /dev/ttyUSB1 pilot
ln -s /dev/ttyUSB1 palm
|
The software package pilot-xfer
uses /dev/pilot by default.
coldsync
defaults to /dev/palm. Create devices
and links as appropriate. Just for fun, you might also want
to create a link from /dev/visor to
/dev/ttyUSB1, just, well, because
we have a visor, not a pilot (or Palm(tm)). The actual
device number may change, depending on how many (active?)
USB-serial devices you have on your system. A message
containing the device actually used is entered into syslog.
Eventually, the idea is to make an entry in the
/proc filesystem
which contains the needed information.
3.7. Using the Modules
For people who compiled the USB code as modules, you
will also need to insert the modules into the running
kernel. When you want to use the visor, you will need to
runt the following commands as root:
/sbin/modprobe usb-uhci
/sbin/modprobe usb-ohci
/sbin/modprobe visor
|
One important note is that the actually driver/device
connection for /dev/ttyUSB* are not
created in the kernel memory until the hotsync button is
pressed. Therefore, if you try to use any software before
pressing the hotsync button, it won't work.