[alsa-devel] ASoC: mmap or read/write?

Clemens Ladisch clemens at ladisch.de
Fri Oct 19 10:58:14 CEST 2012

Mike Looijmans wrote:
> From: Prasant J <pj0585 at gmail.com>
>>> Prasant J wrote:
>>>> I'm writing an alsa application for recording & playing 16 channel audio.
>> I'm working with Beaglebone (ARM Cortex-A8 720 MHz). (Currently
>> failures are for 8 channels 32 bit / 16 bit, but our final target is
>> 16 channels)
>> I have managed to get Audio capture working fine (after certain linux
>> optimizations) but playback is giving under-runs (only when PLAYBACK &
>> CAPTURE run together)
> You must be doing something wrong. I'm doing 32-bit, 16-channel input
> at 51.2kHz on a OMAP-L138 (an ARM9 CPU at 450 MHz)

Playback and capture at the same time seems to be harder for certain
embedded devices.  I don't know if this is a driver bug or a hardware


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