[alsa-devel] [RFC PATCH 0/4] better support for bursty DMA usages

[Pierre-Louis Bossart]

Set of patches to fix issues with hw_ptr fuzziness [1] and increased buffering
 w/ DSPs

1. disable rewinds to allow for new HDaudio SPIB DMA functionality (fetch up to
the application pointer, rewinds not supported)
2. report max in-flight bytes to avoid problems with stale data (late wake-ups,
rewinds)

[1] http://mailman.alsa-project.org/pipermail/alsa-devel/2015-June/093646.html

TODO:
1. fixes and alsa-lib updates (compile-tested only for now)
2. get feedback
3. if supported, set DMA buffering based on negotiation between driver and app (capabilities vs. 
latency needs)

Pierre-Louis Bossart (4):
  ALSA: core: let low-level driver or userspace disable rewinds
  ALSA: core: add .notify callback for pcm ops
  ALSA: core: add report of max dma burst
  ALSA: hda: add default value for max_dma_burst

 include/sound/pcm.h            |  5 +++++
 include/uapi/sound/asound.h    |  6 ++++--
 sound/core/pcm_lib.c           | 19 +++++++++++++++++++
 sound/core/pcm_native.c        | 33 ++++++++++++++++++++++++++++++++-
 sound/pci/hda/hda_controller.c |  1 +
 5 files changed, 61 insertions(+), 3 deletions(-)

-- 
1.9.1