[pulseaudio-discuss] [RFC PATCH] alsa-sink: Reduce hardware pointer update syscalls

[Raymond Yau]

>
> Without patch, with a latency of 48 ms:
>

>
> With the patch, I get the same assertion failed as Peter ("frames > 0").
> With Peter's change, I get this: http://pastebin.com/dWx6fiwT, even with
> no client connected. The reported delay is -5 * default-fragments *
> default-fragment-size-msec.
>

What do mean when you say default-fragments *
default-fragment-size-msec?

Seem pulseaudio using 200ms buffer and 100ms period

it is strange that hwptr is zero when app_ptr is 8820

http://cgit.freedesktop.org/pulseaudio/pulseaudio/plain/src/tests/alsa-time-test.c

Do alsa-time-test run with fillrate 441 with 10ms Interval ?

alsa-sink-USB Audio] alsa-sink.c: Underrun!

E: [alsa-sink-USB Audio] alsa-util.c: snd_pcm_delay() returned a value that
is exceptionally large: -176572 bytes (-1000 ms).

E: [alsa-sink-USB Audio] alsa-util.c: Most likely this is a bug in the ALSA
driver 'snd_usb_audio'. Please report this issue to the ALSA developers.

E: [alsa-sink-USB Audio] alsa-util.c: snd_pcm_dump():

E: [alsa-sink-USB Audio] alsa-util.c: Hardware PCM card 0 'USB Audio CODEC'
device 0 subdevice 0

E: [alsa-sink-USB Audio] alsa-util.c: Its setup is:

E: [alsa-sink-USB Audio] alsa-util.c:   stream       : PLAYBACK

E: [alsa-sink-USB Audio] alsa-util.c:   access       : MMAP_INTERLEAVED

E: [alsa-sink-USB Audio] alsa-util.c:   format       : S16_LE

E: [alsa-sink-USB Audio] alsa-util.c:   subformat    : STD

E: [alsa-sink-USB Audio] alsa-util.c:   channels     : 2

E: [alsa-sink-USB Audio] alsa-util.c:   rate         : 44100

E: [alsa-sink-USB Audio] alsa-util.c:   exact rate   : 44100 (44100/1)

E: [alsa-sink-USB Audio] alsa-util.c:   msbits       : 16

E: [alsa-sink-USB Audio] alsa-util.c:   buffer_size  : 8820

E: [alsa-sink-USB Audio] alsa-util.c:   period_size  : 4410

E: [alsa-sink-USB Audio] alsa-util.c:   period_time  : 100000

E: [alsa-sink-USB Audio] alsa-util.c:   tstamp_mode  : ENABLE

E: [alsa-sink-USB Audio] alsa-util.c:   period_step  : 1

E: [alsa-sink-USB Audio] alsa-util.c:   avail_min    : 4410

E: [alsa-sink-USB Audio] alsa-util.c:   period_event : 1

E: [alsa-sink-USB Audio] alsa-util.c:   start_threshold  : -1

E: [alsa-sink-USB Audio] alsa-util.c:   stop_threshold   : 1156055040

E: [alsa-sink-USB Audio] alsa-util.c:   silence_threshold: 0

E: [alsa-sink-USB Audio] alsa-util.c:   silence_size : 0

E: [alsa-sink-USB Audio] alsa-util.c:   boundary     : 1156055040

E: [alsa-sink-USB Audio] alsa-util.c:   appl_ptr     : 8820

E: [alsa-sink-USB Audio] alsa-util.c:   hw_ptr       : 0
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