On 04/05/2012 10:22 AM, Feng Wei wrote:
When set latency is less than period time, we will assgin working
buffer less than a period size, which will cause unnecessary xrun
and wrong message indicating alsa driver bug.
NAK, I don't think this is correct.
This is tricky stuff though, so don't take my word for it! ;-)
On what machine was this solving a problem for you?
Have you verified it leads to better behaviour (or at least not worse)
on both tsched and non-tsched systems?
I e, try a VOIP call with ~20 ms of latency, on a desktop machine that
has 2 x 1s periods, running in tsched mode. I'm guessing the latency
will be unacceptable with this patch applied.
Signed-off-by: Feng Wei<[email protected]>
---
src/modules/alsa/alsa-sink.c | 6 +++---
src/modules/alsa/alsa-source.c | 6 +++---
2 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/src/modules/alsa/alsa-sink.c b/src/modules/alsa/alsa-sink.c
index 5a4b606..a53fb6f 100644
--- a/src/modules/alsa/alsa-sink.c
+++ b/src/modules/alsa/alsa-sink.c
@@ -953,10 +953,10 @@ static int update_sw_params(struct userdata *u) {
b = pa_usec_to_bytes(latency,&u->sink->sample_spec);
- /* We need at least one sample in our buffer */
+ /* We need at least one period and one sample in our buffer to
avoid underflow */
- if (PA_UNLIKELY(b< u->frame_size))
- b = u->frame_size;
+ if (PA_UNLIKELY(b< u->frame_size + u->fragment_size))
+ b = u->frame_size + u->fragment_size;
u->hwbuf_unused = PA_LIKELY(b< u->hwbuf_size) ? (u->hwbuf_size -
b) : 0;
}
diff --git a/src/modules/alsa/alsa-source.c b/src/modules/alsa/alsa-source.c
index 27fd3b9..8c41ca6 100644
--- a/src/modules/alsa/alsa-source.c
+++ b/src/modules/alsa/alsa-source.c
@@ -876,10 +876,10 @@ static int update_sw_params(struct userdata *u) {
b = pa_usec_to_bytes(latency,&u->source->sample_spec);
- /* We need at least one sample in our buffer */
+ /* We need at least one period and one sample in our buffer to
avoid overflow */
- if (PA_UNLIKELY(b< u->frame_size))
- b = u->frame_size;
+ if (PA_UNLIKELY(b< u->frame_size + u->fragment_size))
+ b = u->frame_size + u->fragment_size;
u->hwbuf_unused = PA_LIKELY(b< u->hwbuf_size) ? (u->hwbuf_size -
b) : 0;
}
--
David Henningsson, Canonical Ltd.
http://launchpad.net/~diwic
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