On 02/06/2015 10:16 AM, Tim Cussins wrote:
We introduce the kernel-side of the START_AT ioctl.
struct runtime is updated to hold information about the currently active start_at timer, if any. This facilitates cancellation via snd_pcm_start_at_abort(), and querying via snd_pcm_status().
struct snd_start_at holds a startat operation and its arguments.
Signed-off-by: Tim Cussins timcussins@eml.cc
diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h index 0e88e7a..2943e1a 100644 --- a/include/uapi/sound/asound.h +++ b/include/uapi/sound/asound.h @@ -421,7 +421,10 @@ struct snd_pcm_status { snd_pcm_state_t suspended_state; /* suspended stream state */ __u32 reserved_alignment; /* must be filled with zero */ struct timespec audio_tstamp; /* from sample counter or wall clock */
- unsigned char reserved[56-sizeof(struct timespec)]; /* must be filled with zero */
- int startat_pending; /* 1 if a start_at timer is pending, 0 otherwise */
- int startat_clock_type; /* start_at clock type, if pending */
- struct timespec startat_start_time; /* start_at start time, if pending */
- unsigned char reserved[48-(2*sizeof(struct timespec))]; /* must be filled with zero */
};
struct snd_pcm_mmap_status { @@ -473,6 +476,34 @@ enum { SNDRV_PCM_TSTAMP_TYPE_LAST = SNDRV_PCM_TSTAMP_TYPE_MONOTONIC_RAW, };
+enum {
- SNDRV_PCM_STARTAT_OP_SET = 0,
- SNDRV_PCM_STARTAT_OP_CANCEL,
- SNDRV_PCM_STARTAT_OP_STATUS,
- SNDRV_PCM_STARTAT_OP_LAST = SNDRV_PCM_STARTAT_OP_STATUS,
+};
+enum {
SNDRV_PCM_STARTAT_CLOCK_TYPE_GETTIMEOFDAY = 0,SNDRV_PCM_STARTAT_CLOCK_TYPE_MONOTONIC,SNDRV_PCM_STARTAT_CLOCK_TYPE_LINK,SNDRV_PCM_STARTAT_CLOCK_TYPE_LAST = SNDRV_PCM_STARTAT_CLOCK_TYPE_LINK,+};
Looks like you went back to the original design with all clocks mixed. I think it's a better idea to split system timers and audio clocks. And you are missing MONOTONIC_RAW (no NTP corrections).
+struct snd_start_at {
- int op; /* startat operation to be performed */
- union { /* fields for setting a startat timer */
struct {int clock_type; /* clock type e.g. SNDRV_PCM_STARTAT_CLOCK_TYPE_GETTIMEOFDAY */struct timespec start_time; /* start time */} set;struct {int clock_type;struct timespec current_time;} status;- } args;
+};
/* channel positions */ enum { SNDRV_CHMAP_UNKNOWN = 0, @@ -551,6 +582,8 @@ enum { #define SNDRV_PCM_IOCTL_READN_FRAMES _IOR('A', 0x53, struct snd_xfern) #define SNDRV_PCM_IOCTL_LINK _IOW('A', 0x60, int) #define SNDRV_PCM_IOCTL_UNLINK _IO('A', 0x61) +#define SNDRV_PCM_IOCTL_START_AT _IOW('A', 0x62, struct snd_start_at)
/*****************************************************************************
*