Hi,
I am using 2.6.32 with omap3evm board.
The audio skips a couple of frames at the first interrupt on palyback
(TWL4030) when I use small period size (10msec). But the same
parameters work fine on capture. With large period/frame size, it
works fine also.
The skip causes extra delays (30msec at 16kHz) which I tried to
minimize. From omap-pcm.c the similar parameters are used to setup DMA
for both playback and capture, but why only playback does the skip?
The following are logs with xrun_debug=9:
root@omap3evm:~# aplay -f S16_LE -r 16000 -c 2 -d 1 -F 10000 -B 80000
-R 10000 -T 160000 < /dev/urandom
Oct 26 11:04:11 omap3evm user.debug kernel: ALSA
sound/core/pcm_lib.c:250: period_update: pcmC0D0p:0:
pos=0x280/0xa0/0x500, hwptr=0x0, hw_base=0x0, hw_intr=0x0
Oct 26 11:04:11 omap3evm user.debug kernel: ALSA
sound/core/pcm_lib.c:334: PCM: Lost interrupts? (stream=0, delta=480,
intr_ptr=160)
Oct 26 11:04:11 omap3evm user.debug kernel: ALSA
sound/core/pcm_lib.c:250: period_update: pcmC0D0p:0:
pos=0x3c0/0xa0/0x500, hwptr=0x320, hw_base=0x0, hw_intr=0x320
Oct 26 11:04:11 omap3evm user.debug kernel: ALSA
sound/core/pcm_lib.c:250: period_update: pcmC0D0p:0:
pos=0x0/0xa0/0x500, hwptr=0x460, hw_base=0x0, hw_intr=0x460
Oct 26 11:04:11 omap3evm user.debug kernel: ALSA
sound/core/pcm_lib.c:250: period_update: pcmC0D0p:0:
pos=0x140/0xa0/0x500, hwptr=0x5a0, hw_base=0x500, hw_intr=0x5a0
Oct 26 11:04:11 omap3evm user.debug kernel: ALSA
sound/core/pcm_lib.c:250: period_update: pcmC0D0p:0:
pos=0x280/0xa0/0x500, hwptr=0x6e0, hw_base=0x500, hw_intr=0x6e0
Oct 26 11:04:11 omap3evm user.debug kernel: ALSA
sound/core/pcm_lib.c:250: period_update: pcmC0D0p:0:
pos=0x3c0/0xa0/0x500, hwptr=0x820, hw_base=0x500, hw_intr=0x820
Oct 26 11:04:11 omap3evm user.debug kernel: ALSA
sound/core/pcm_lib.c:250: period_update: pcmC0D0p:0:
pos=0x0/0xa0/0x500, hwptr=0x960, hw_base=0x500, hw_intr=0x960
root@omap3evm:~# arecord -f S16_LE -r 16000 -c 2 -d 1 -F 10000 -B 80000
-R 10000 -T 160000 /tmp/test.pcm
Oct 26 11:04:13 omap3evm user.debug kernel: ALSA
sound/core/pcm_lib.c:250: period_update: pcmC0D0c:0:
pos=0x140/0xa0/0x500, hwptr=0xa0, hw_base=0x0, hw_intr=0xa0
Oct 26 11:04:13 omap3evm user.debug kernel: ALSA
sound/core/pcm_lib.c:250: period_update: pcmC0D0c:0:
pos=0x280/0xa0/0x500, hwptr=0x1e0, hw_base=0x0, hw_intr=0x1e0
Oct 26 11:04:13 omap3evm user.debug kernel: ALSA
sound/core/pcm_lib.c:250: period_update: pcmC0D0c:0:
pos=0x3c0/0xa0/0x500, hwptr=0x320, hw_base=0x0, hw_intr=0x320
root@omap3evm:~# aplay -f S16_LE -r 16000 -c 2 -d 1 -F 40000 -B 320000
-R 40000 -T 640000 < /dev/urandom
Oct 26 11:18:46 omap3evm user.debug kernel: ALSA
sound/core/pcm_lib.c:250: period_update: pcmC0D0p:0:
pos=0x400/0x200/0x1400, hwptr=0x200, hw_base=0x0, hw_intr=0x200
Oct 26 11:18:46 omap3evm user.debug kernel: ALSA
sound/core/pcm_lib.c:250: period_update: pcmC0D0p:0:
pos=0x800/0x200/0x1400, hwptr=0x600, hw_base=0x0, hw_intr=0x600
Oct 26 11:18:46 omap3evm user.debug kernel: ALSA
sound/core/pcm_lib.c:250: period_update: pcmC0D0p:0:
pos=0xc00/0x200/0x1400, hwptr=0xa00, hw_base=0x0, hw_intr=0xa00
Best regards,
Ying Lin
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