[alsa-devel] [PATCH v3 0/3] introduce device_buffer

Jaroslav Kysela perex at perex.cz
Fri Aug 31 12:41:32 CEST 2012


Date 31.8.2012 03:14, Vinod Koul wrote:
> Old wine in a new bottle with added flavour now.
> Based on our discussions in LPC, now we will report the combined delay value as
> sum of the buffering done in driver and hardware. This is used to report delay


> Additionally we tell pcm what is buffer in device/driver, this is used to check
> for error calulcations

I'm afraid, but this won't work for the mmaped appl_ptr / hw_ptr,
because the checks are done outside the kernel - in alsa-lib. I believe
that this API should be enhanced, too. But the question is, how to pass
two values (hwptr, device_buffer) atomically to the user space without
locks for x86.

					Jaroslav

> 
> Vinod Koul (3):
>   ALSA: pcm - introduce device_buffer
>   ASoC: add device_buffer in asoc
>   ASoC: mid-x86 - implement buffer query in sst_platform driver
> 
>  include/sound/pcm.h              |    1 +
>  include/sound/soc-dai.h          |    6 ++++++
>  include/sound/soc.h              |    6 ++++++
>  sound/core/pcm_lib.c             |   10 +++++++++-
>  sound/soc/mid-x86/sst_platform.c |   23 +++++++++++++++++++++++
>  sound/soc/mid-x86/sst_platform.h |    4 +++-
>  sound/soc/soc-pcm.c              |   13 ++++++++++++-
>  7 files changed, 60 insertions(+), 3 deletions(-)
> 


-- 
Jaroslav Kysela <perex at perex.cz>
Linux Kernel Sound Maintainer
ALSA Project; Red Hat, Inc.


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