From: Alan Horstmann Date: Mon, 4 Jun 2007 21:11:23 +0000 (+0200) Subject: [ALSA] More description on duplex streams with OSS emulation X-Git-Tag: v3.12-rc1~27809^2~78 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=1919de0a9e939ef4f9453ef1630ca1345991e144;p=kernel%2Fkernel-generic.git [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 Signed-off-by: Takashi Iwai Signed-off-by: Jaroslav Kysela --- diff --git a/Documentation/sound/alsa/OSS-Emulation.txt b/Documentation/sound/alsa/OSS-Emulation.txt index ec2a025..bfa0c9a 100644 --- a/Documentation/sound/alsa/OSS-Emulation.txt +++ b/Documentation/sound/alsa/OSS-Emulation.txt @@ -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 ====================