From: Alan The tty driver write method is different to the usual fops device write methods as the buffer is already in kernel space. Clarify the docs since someone writing a driver made that mistake. Signed-off-by: Alan Cox Signed-off-by: Andrew Morton --- Documentation/tty.txt | 4 +++- 1 files changed, 3 insertions(+), 1 deletion(-) diff -puN Documentation/tty.txt~tty-clarify-documentation-of-write Documentation/tty.txt --- a/Documentation/tty.txt~tty-clarify-documentation-of-write +++ a/Documentation/tty.txt @@ -108,7 +108,9 @@ hardware driver through the function poi 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 _