[ALSA] More description on duplex streams with OSS emulation

Add paragraph to the OSS document to clarify correct use of duplex streams.

Signed-off-by: Alan Horstmann <gineera@aspect135.co.uk>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>
This commit is contained in:
Alan Horstmann 2007-06-04 23:11:23 +02:00 committed by Jaroslav Kysela
parent 3b194401a3
commit 1919de0a9e

View file

@ -278,6 +278,21 @@ current mixer configuration by reading and writing the whole file
image.
Duplex Streams
==============
Note that when attempting to use a single device file for playback and
capture, the OSS API provides no way to set the format, sample rate or
number of channels different in each direction. Thus
io_handle = open("device", O_RDWR)
will only function correctly if the values are the same in each direction.
To use different values in the two directions, use both
input_handle = open("device", O_RDONLY)
output_handle = open("device", O_WRONLY)
and set the values for the corresponding handle.
Unsupported Features
====================