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| author |   Takashi Iwai <tiwai@suse.de> | 2019-11-17 09:53:04 +0100 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2019-11-20 19:39:54 +0100 |
| commit | f6161f379c5d455bcedc2cbb1968235a85e151c1 (patch) | |
| tree | a6ad1e75aac3b7237887026bc1286a24b0d831c4 /Documentation/sound | |
| parent | ALSA: pcm: Allow NULL ioctl ops (diff) | |
| download | wireguard-linux-f6161f379c5d455bcedc2cbb1968235a85e151c1.tar.xz wireguard-linux-f6161f379c5d455bcedc2cbb1968235a85e151c1.zip | |
ALSA: docs: Update document about the default PCM ioctl ops
Mention that it's completely optional now.
Link: https://lore.kernel.org/r/20191117085308.23915-5-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'Documentation/sound')
| -rw-r--r-- | Documentation/sound/kernel-api/writing-an-alsa-driver.rst | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/Documentation/sound/kernel-api/writing-an-alsa-driver.rst b/Documentation/sound/kernel-api/writing-an-alsa-driver.rst index 1086b35db2af..145bf6aad7cb 100644 --- a/Documentation/sound/kernel-api/writing-an-alsa-driver.rst +++ b/Documentation/sound/kernel-api/writing-an-alsa-driver.rst @@ -1341,7 +1341,6 @@ shows only the skeleton, how to build up the PCM interfaces. static struct snd_pcm_ops snd_mychip_playback_ops = { .open = snd_mychip_playback_open, .close = snd_mychip_playback_close, - .ioctl = snd_pcm_lib_ioctl, .hw_params = snd_mychip_pcm_hw_params, .hw_free = snd_mychip_pcm_hw_free, .prepare = snd_mychip_pcm_prepare, @@ -1353,7 +1352,6 @@ shows only the skeleton, how to build up the PCM interfaces. static struct snd_pcm_ops snd_mychip_capture_ops = { .open = snd_mychip_capture_open, .close = snd_mychip_capture_close, - .ioctl = snd_pcm_lib_ioctl, .hw_params = snd_mychip_pcm_hw_params, .hw_free = snd_mychip_pcm_hw_free, .prepare = snd_mychip_pcm_prepare, @@ -1456,7 +1454,6 @@ The operators are defined typically like this: static struct snd_pcm_ops snd_mychip_playback_ops = { .open = snd_mychip_pcm_open, .close = snd_mychip_pcm_close, - .ioctl = snd_pcm_lib_ioctl, .hw_params = snd_mychip_pcm_hw_params, .hw_free = snd_mychip_pcm_hw_free, .prepare = snd_mychip_pcm_prepare, @@ -1913,7 +1910,10 @@ ioctl callback ~~~~~~~~~~~~~~ This is used for any special call to pcm ioctls. But usually you can -pass a generic ioctl callback, :c:func:`snd_pcm_lib_ioctl()`. +leave it as NULL, then PCM core calls the generic ioctl callback +function :c:func:`snd_pcm_lib_ioctl()`. If you need to deal with the +unique setup of channel info or reset procedure, you can pass your own +callback function here. hw_params callback ~~~~~~~~~~~~~~~~~~~ |