----- Original Message -----
From: "Jarkko Nikula" <jarkko.nikula@xxxxxxxxx>
To: "ext shekhar, chandra" <x0044955@xxxxxx>
Cc: "Tony Lindgren" <tony@xxxxxxxxxxx>; <linux-omap@xxxxxxxxxxxxxxx>
Sent: Wednesday, September 10, 2008 4:44 PM
Subject: Re: [PATCH 1/2] McBSP DMA support for 34xx
On Wed, 10 Sep 2008 15:47:34 +0530
"ext shekhar, chandra" <x0044955@xxxxxx> wrote:
Most importantly,
4> McBSP buffer ( To save power, for 34xx).
OMAP3430 McBSP interface 2 has 5k buffer for audio. handling of this
buffer should be specific to McBSP.
Actually it's not specific to McBSP only. I haven't paid attention into
these HW buffering issues but they have an effect. Like
- IRCC ALSA expects that playback/record is really stopped when trigger
callback returns
- How HW buffering affects pointer callback? Some low-latency audio
algorithms require that buffer position is known very precisely. E.g.
if modifying already queued audio buffer content but which is not
played out yet
This harware buffer is not user accessible, but during data transfer it is
related to dma transfer.
During data transfer instead of element sync, packet sync data transfer can be
used.
DMA request length can be configured buffer threshold and packet sync transfer
can be used instead of element sync.
Jarkko
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