Test the Layered Driver

To test the lyr driver, write a message to the lyr device and verify that the message displays on the lyr_targ device.

Example 14–3 Write a Short Message to the Layered Device

In this example, the lyr_targ device is the console of the system where the lyr device is installed.

If the display you are viewing is also the display for the console device of the system where the lyr device is installed, note that writing to the console will corrupt your display. The console messages will appear outside your window system. You will need to redraw or refresh your display after testing the lyr driver.

If the display you are viewing is not the display for the console device of the system where the lyr device is installed, log into or otherwise gain a view of the display of the target console device.

The following command writes a very brief message to the lyr device:

# echo "\n\n\t===> Hello World!! <===\n" > /devices/pseudo/lyr@1:node

You should see the following messages displayed on the target console:

console login:

    ===> Hello World!! <===

lyr: 
lyr_open: opened target '/dev/console' successfully on inst 1
lyr: 
lyr_close: closed target successfully on inst 1

The messages from lyr_open() and lyr_close() come from the cmn_err(9F) calls in the lyr_open() and lyr_close() entry points.

Example 14–4 Write a Longer Message to the Layered Device

The following command writes a longer message to the lyr device:

# cat lyr.conf > /devices/pseudo/lyr@1:node

You should see the following messages displayed on the target console:

lyr: 
lyr_open: opened target '/dev/console' successfully on inst 1
#
# Use is subject to license terms.
#
#pragma ident   "%Z%%M% %I%     %E% SMI"

name="lyr" parent="pseudo" instance=1;
lyr_targ="/dev/console";
lyr: 
lyr_close: closed target successfully on inst 1

Example 14–5 Change the Target Device

To change the target device, edit /usr/kernel/drv/lyr.conf and change the value of the lyr_targ property to be a path to a different target device. For example, the target device could be the output of a tty command in a local terminal. An example of such a device path is /dev/pts/4.

Make sure the lyr device is not in use before you update the driver to use the new target device.

# modinfo -c | grep lyr
174          3 lyr                              UNLOADED/UNINSTALLED

Use the update_drv(1M) command to reload the lyr.conf configuration file:

# update_drv lyr

Write a message to the lyr device again and verify that the message displays on the new lyr_targ device.