On 04/05/2012 10:59 AM, Feng Wei wrote:
David,
I'd met xrun on some embedded platform, which will only report hw_ptr
at period boundary. Maybe it shouldn't use tsched, I'm not sure. Sorry
for inconvenience.
Actually it does raise an important question about how we deal with
platforms that have bad hw_ptr granularity. We don't to that very well
today.
Also is there much difference, powersave wise, between running in
non-tsched and tsched mode? If there isn't, maybe using non-tsched for
your particular device is the best option (if it works).
2012/4/5 David Henningsson<[email protected]>:
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
--
David Henningsson, Canonical Ltd.
http://launchpad.net/~diwic
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