Here's another appl_ptr related patch to the alsa soc mpc5200 ac97 driver. This
time the patch is to fix a problem with not correctly handling appl_ptr
wrapping back around to the beginning of the buffer.
I haven't yet seen a symptom related to this. This came up when I was chatting
with Jon Smirl about another bug I was examining. Right now there is another
problem that is preventing me from playing really long audio streams.
Let me know if this is the wrong approach.
- John
The code in psc_dma_bcom_enqueue_tx() didn't account for the fact that
s->runtime->control->appl_ptr can wrap around to the beginning of the
buffer. This change fixes this problem.
Signed-off-by: John Bonesio <bones@xxxxxxxxxxxx>
---
sound/soc/fsl/mpc5200_dma.c | 17 +++++++++++++++++
1 files changed, 17 insertions(+), 0 deletions(-)
diff --git a/sound/soc/fsl/mpc5200_dma.c b/sound/soc/fsl/mpc5200_dma.c
index cfe0ea4..2551c58 100644
--- a/sound/soc/fsl/mpc5200_dma.c
+++ b/sound/soc/fsl/mpc5200_dma.c
@@ -70,6 +70,23 @@ static void psc_dma_bcom_enqueue_next_buffer(struct psc_dma_stream *s)
static void psc_dma_bcom_enqueue_tx(struct psc_dma_stream *s)
{
+ if (s->appl_ptr > s->runtime->control->appl_ptr) {
+ /*
+ * In this case s->runtime->control->appl_ptr has wrapped around.
+ * Play the data to the end of the boundary, then wrap our own
+ * appl_ptr back around.
+ */
+ while (s->appl_ptr < s->runtime->boundary) {
+ if (bcom_queue_full(s->bcom_task))
+ return;
+
+ s->appl_ptr += s->period_size;
+
+ psc_dma_bcom_enqueue_next_buffer(s);
+ }
+ s->appl_ptr -= s->runtime->boundary;
+ }
+
while (s->appl_ptr < s->runtime->control->appl_ptr) {
if (bcom_queue_full(s->bcom_task))
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