[alsa-devel] [PATCH 1/3] ALSA: compress_core: Update calc_avail to use cumulative values

Charles Keepax ckeepax at opensource.wolfsonmicro.com
Wed Apr 10 11:57:02 CEST 2013

On Tue, Apr 09, 2013 at 04:32:30PM +0530, Vinod Koul wrote:
> On Wed, Apr 03, 2013 at 01:13:27PM +0100, Charles Keepax wrote:
> > The app_pointer is managed locally by the compress core for memory
> > mapped DSPs but for DSPs that are not memory mapped this would have to
> > be manually updated from within the DSP driver itself, which is hardly
> > very idiomatic.
> app pointer means what has been written into DSP buffer, no matter if its memory
> mapped or not. This is updated after .copy returns so if you have been asked to
> copy 100bytes, and return of .copy, app pointer is incremented by 100, so why is
> that not true for you?

Currently though app_pointer is not updated after a copy callback
the cumulative values are updated, but not app_pointer.
app_pointer is only updated in the case were we don't have a copy
callback and the buffer is managed by the compressed core.

I am quite happy to change that or remove this comment from the change
log if we prefer but as it currently stands app_pointer will not
be updated for systems that use a copy callback by the compress


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