ALSA: pcm: Introduce protocol version field to sw_params
For controlling the new fields more strictly, add sw_params.proto
field indicating the protocol version of the user-space. User-space
should fill the SNDRV_PCM_VERSION value it's built with, then kernel
can know whether the new fields should be evaluated or not.
And now tstamp_type field is evaluated only when the valid value is
set there. This avoids the wrong override of tstamp_type to zero,
which is SNDRV_PCM_TSTAMP_TYPE_GETTIMEOFDAY.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h
index a7e062f..32168f7 100644
--- a/include/uapi/sound/asound.h
+++ b/include/uapi/sound/asound.h
@@ -391,8 +391,8 @@
snd_pcm_uframes_t silence_threshold; /* min distance from noise for silence filling */
snd_pcm_uframes_t silence_size; /* silence block size */
snd_pcm_uframes_t boundary; /* pointers wrap point */
- unsigned int tstamp_type; /* timestamp type */
- int pads; /* alignment, reserved */
+ unsigned int proto; /* protocol version */
+ unsigned int tstamp_type; /* timestamp type (req. proto >= 2.0.12) */
unsigned char reserved[56]; /* reserved for future */
};