On 7/10/14, 8:04 AM, Takashi Iwai wrote:
For allowing adjusting the timestamp type on the fly, add it to sw_params. The existing ioctl is still kept for compatibility.
I have strong objections to this extension. It will result in a discontinuity in the timestamps reported in pcm_status without a clear indication of what timestamp is reported (when does this change occur?), and it's completely unclear how userspace would handle a step (positive or negative) between ntp-adjusted and non-ntp-adjusted times. For apps that make use of the audio_time reported with a wall clock this could lead to complete nonsense. I would have no problems if this was a fixed parameter defined once before audio streaming starts.
Along with this, increment the PCM protocol version.
The extension was suggested by Clemens Ladisch.
Signed-off-by: Takashi Iwai tiwai@suse.de
include/uapi/sound/asound.h | 6 ++++-- sound/core/pcm_native.c | 3 +++ 2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h index cbf7dc850a46..a7e062f91f39 100644 --- a/include/uapi/sound/asound.h +++ b/include/uapi/sound/asound.h @@ -139,7 +139,7 @@ struct snd_hwdep_dsp_image {
******************************************************************************/
-#define SNDRV_PCM_VERSION SNDRV_PROTOCOL_VERSION(2, 0, 11) +#define SNDRV_PCM_VERSION SNDRV_PROTOCOL_VERSION(2, 0, 12)
typedef unsigned long snd_pcm_uframes_t; typedef signed long snd_pcm_sframes_t; @@ -391,7 +391,9 @@ struct snd_pcm_sw_params { 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 char reserved[64]; /* reserved for future */
unsigned int tstamp_type; /* timestamp type */
int pads; /* alignment, reserved */
unsigned char reserved[56]; /* reserved for future */ };
struct snd_pcm_channel_info {
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c index 2372c49a8e84..81dedc381efd 100644 --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -543,6 +543,8 @@ static int snd_pcm_sw_params(struct snd_pcm_substream *substream,
if (params->tstamp_mode > SNDRV_PCM_TSTAMP_LAST) return -EINVAL;
- if (params->tstamp_type > SNDRV_PCM_TSTAMP_TYPE_LAST)
return -EINVAL;@@ -557,6 +559,7 @@ static int snd_pcm_sw_params(struct snd_pcm_substream *substream, err = 0; snd_pcm_stream_lock_irq(substream); runtime->tstamp_mode = params->tstamp_mode;
- runtime->tstamp_type = params->tstamp_type; runtime->period_step = params->period_step; runtime->control->avail_min = params->avail_min; runtime->start_threshold = params->start_threshold;