When forwarding or rewinding, the frame counter was not updated. This could result in corrupted channel status words or misplaced Z-type preamble.
Signed-off-by: Alexander E. Patrakov patrakov@gmail.com --- v2: As suggested by David Henningsson, patch a copy of snd_pcm_plugin_fast_ops at runtime instead of making all plugin finctions non-static. But, contrary to his proposal, I made fast_ops just a part of struct snd_pcm_iec958, because the needed lifetime is exactly the same.
I still have no hardware to test this, and I strongly suspect that the patch is wrong, because nobody else uses dynamic allocation of fast_ops. A potentially suspicious operation would be to place a plug on top of this, because plug copies fast_ops around. However, each time it closes a slave, it also resets fast_ops to something sane, or at least I think so.
src/pcm/pcm_iec958.c | 37 ++++++++++++++++++++++++++++++++++++- src/pcm/pcm_plugin.c | 4 ++-- src/pcm/pcm_plugin.h | 6 ++++++ 3 files changed, 44 insertions(+), 3 deletions(-)
diff --git a/src/pcm/pcm_iec958.c b/src/pcm/pcm_iec958.c index d81b0a1..0c61fc1 100644 --- a/src/pcm/pcm_iec958.c +++ b/src/pcm/pcm_iec958.c @@ -62,6 +62,7 @@ struct snd_pcm_iec958 { unsigned char status[24]; unsigned int byteswap; unsigned char preamble[3]; /* B/M/W or Z/X/Y */ + snd_pcm_fast_ops_t fops; };
enum { PREAMBLE_Z, PREAMBLE_X, PREAMBLE_Y }; @@ -416,6 +417,35 @@ static void snd_pcm_iec958_dump(snd_pcm_t *pcm, snd_output_t *out) snd_pcm_dump(iec->plug.gen.slave, out); }
+static snd_pcm_sframes_t snd_pcm_iec958_rewind(snd_pcm_t *pcm, snd_pcm_uframes_t frames) +{ + unsigned int counter_decrement; + snd_pcm_iec958_t *iec = pcm->private_data; + snd_pcm_sframes_t result = snd_pcm_plugin_rewind(pcm, frames); + if (result <= 0) + return result; + + counter_decrement = result % 192; + iec->counter += 192 - counter_decrement; + iec->counter %= 192; + return result; +} + +static snd_pcm_sframes_t snd_pcm_iec958_forward(snd_pcm_t *pcm, snd_pcm_uframes_t frames) + +{ + unsigned int counter_increment; + snd_pcm_iec958_t *iec = pcm->private_data; + snd_pcm_sframes_t result = snd_pcm_plugin_rewind(pcm, frames); + if (result <= 0) + return result; + + counter_increment = result % 192; + iec->counter += counter_increment; + iec->counter %= 192; + return result; +} + static const snd_pcm_ops_t snd_pcm_iec958_ops = { .close = snd_pcm_generic_close, .info = snd_pcm_generic_info, @@ -495,7 +525,12 @@ int snd_pcm_iec958_open(snd_pcm_t **pcmp, const char *name, snd_pcm_format_t sfo return err; } pcm->ops = &snd_pcm_iec958_ops; - pcm->fast_ops = &snd_pcm_plugin_fast_ops; + + iec->fops = snd_pcm_plugin_fast_ops; + iec->fops.rewind = snd_pcm_iec958_rewind; + iec->fops.forward = snd_pcm_iec958_forward; + pcm->fast_ops = &iec->fops; + pcm->private_data = iec; pcm->poll_fd = slave->poll_fd; pcm->poll_events = slave->poll_events; diff --git a/src/pcm/pcm_plugin.c b/src/pcm/pcm_plugin.c index 17157e8..4ddf10c 100644 --- a/src/pcm/pcm_plugin.c +++ b/src/pcm/pcm_plugin.c @@ -201,7 +201,7 @@ static snd_pcm_sframes_t snd_pcm_plugin_rewindable(snd_pcm_t *pcm) return snd_pcm_mmap_hw_avail(pcm); }
-static snd_pcm_sframes_t snd_pcm_plugin_rewind(snd_pcm_t *pcm, snd_pcm_uframes_t frames) +snd_pcm_sframes_t snd_pcm_plugin_rewind(snd_pcm_t *pcm, snd_pcm_uframes_t frames) { snd_pcm_plugin_t *plugin = pcm->private_data; snd_pcm_sframes_t n = snd_pcm_mmap_hw_avail(pcm); @@ -229,7 +229,7 @@ static snd_pcm_sframes_t snd_pcm_plugin_forwardable(snd_pcm_t *pcm) return snd_pcm_mmap_avail(pcm); }
-static snd_pcm_sframes_t snd_pcm_plugin_forward(snd_pcm_t *pcm, snd_pcm_uframes_t frames) +snd_pcm_sframes_t snd_pcm_plugin_forward(snd_pcm_t *pcm, snd_pcm_uframes_t frames) { snd_pcm_plugin_t *plugin = pcm->private_data; snd_pcm_sframes_t n = snd_pcm_mmap_avail(pcm); diff --git a/src/pcm/pcm_plugin.h b/src/pcm/pcm_plugin.h index 7ee7c7f..19e82c3 100644 --- a/src/pcm/pcm_plugin.h +++ b/src/pcm/pcm_plugin.h @@ -58,8 +58,14 @@ typedef struct { snd1_pcm_plugin_undo_read_generic #define snd_pcm_plugin_undo_write_generic \ snd1_pcm_plugin_undo_write_generic +#define snd_pcm_plugin_rewind \ + snd1_pcm_plugin_rewind +#define snd_pcm_plugin_forward \ + snd1_pcm_plugin_forward
void snd_pcm_plugin_init(snd_pcm_plugin_t *plugin); +snd_pcm_sframes_t snd_pcm_plugin_rewind(snd_pcm_t *pcm, snd_pcm_uframes_t frames); +snd_pcm_sframes_t snd_pcm_plugin_forward(snd_pcm_t *pcm, snd_pcm_uframes_t frames);
extern const snd_pcm_fast_ops_t snd_pcm_plugin_fast_ops;