Console Drivers
===============
-The linux kernel has 2 general types of console drivers. The first type is
+The Linux kernel has 2 general types of console drivers. The first type is
assigned by the kernel to all the virtual consoles during the boot process.
This type will be called 'system driver', and only one system driver is allowed
to exist. The system driver is persistent and it can never be unloaded, though
occupied by the system driver. In the same token, if the modular driver is
released by the console, the system driver will take over.
-Modular drivers, from the programmer's point of view, has to call:
+Modular drivers, from the programmer's point of view, have to call:
do_take_over_console() - load and bind driver to console layer
- give_up_console() - unload driver, it will only work if driver is fully unbond
+ give_up_console() - unload driver; it will only work if driver
+ is fully unbound
In newer kernels, the following are also available:
cat /sys/class/vtconsole/vtcon0/name
(S) VGA+
- '(S)' stands for a (S)ystem driver, ie, it cannot be directly
+ '(S)' stands for a (S)ystem driver, i.e., it cannot be directly
commanded to bind or unbind
'VGA+' is the name of the driver
for rebooting the kernel. For regular users who may want to switch from
framebuffer console to VGA console and vice versa, this feature also makes
this possible. (NOTE NOTE NOTE: Please read fbcon.txt under Documentation/fb
-for more details).
+for more details.)
Notes for developers:
=====================
console drivers must follow these guidelines:
1. All drivers, except system drivers, must call either do_register_con_driver()
- or do_take_over_console(). do_register_con_driver() will just add the driver to
- the console's internal list. It won't take over the
+ or do_take_over_console(). do_register_con_driver() will just add the driver
+ to the console's internal list. It won't take over the
console. do_take_over_console(), as it name implies, will also take over (or
bind to) the console.