Merge branch 'kvm-updates-2.6.27' of git://git.kernel.org/pub/scm/linux/kernel/git...

[pandora-kernel.git] / Documentation / tty.txt

diff --git a/Documentation/tty.txt b/Documentation/tty.txt
index 5f799e6..8e65c44 100644 (file)
--- a/Documentation/tty.txt
+++ b/Documentation/tty.txt
@@ -108,7 +108,9 @@ hardware driver through the function pointers within the tty->driver
 structure:
 
 write()                        Write a block of characters to the tty device.
 structure:
 
 write()                        Write a block of characters to the tty device.

-                       Returns the number of characters accepted.
+                       Returns the number of characters accepted. The
+                       character buffer passed to this method is already
+                       in kernel space.

 
 put_char()             Queues a character for writing to the tty device.
                        If there is no room in the queue, the character is
 
 put_char()             Queues a character for writing to the tty device.
                        If there is no room in the queue, the character is


@@ -130,6 +132,14 @@ set_termios()              Notify the tty driver that the device's termios
                        tty->termios. Previous settings should be passed in
                        the "old" argument.
 
                        tty->termios. Previous settings should be passed in
                        the "old" argument.
 

+                       The API is defined such that the driver should return
+                       the actual modes selected. This means that the
+                       driver function is responsible for modifying any
+                       bits in the request it cannot fulfill to indicate
+                       the actual modes being used. A device with no
+                       hardware capability for change (eg a USB dongle or
+                       virtual port) can provide NULL for this method.
+

 throttle()             Notify the tty driver that input buffers for the
                        line discipline are close to full, and it should
                        somehow signal that no more characters should be
 throttle()             Notify the tty driver that input buffers for the
                        line discipline are close to full, and it should
                        somehow signal that no more characters should be