[PATCH 0/2] [Jaunty] LP: #190754, #235990, #320875, #330814, #333565, #344057, #343254 -- Fix hw_ptr instability causing abysmal PulseAudio performance

Daniel T Chen seven.steps at gmail.com
Thu Mar 26 04:12:48 UTC 2009

Hash: SHA1

hw_ptr tracking and calculations have been broken for quite some time in
ALSA-kernel. The effects have been apparent: throughout 8.10 and 9.04
development (particularly during the latter), users have complained of
crackling and popping in a variety of drivers and applications. The
popularity of HDA codecs and the advent of PulseAudio have exposed
instability in hw_ptr and wrong assumptions in delay calculations.
Indeed, PulseAudio has been arguably the worst victim, experiencing
crashes and generating copious syslog debugging output among other

The two changesets from my for-kernel-team branch are backported from
Takashi's sound-2.6 tree and are queued for inclusion in 2.6.30.

These changes have been well tested in my custom builds on
kernel.ubuntu.com/~dtchen and have received extremely positive feedback.
- From all indications, there are no regressions from behaviour using
direct ALSA and JACK in previous Ubuntu releases, and PulseAudio
behaviour is markedly improved.

Please apply to Jaunty.

Daniel T Chen (2):
   UBUNTU: Don't trust hw-ptr blindly
   UBUNTU: Apply further pcm_lib updates for hw_ptr

  sound/core/pcm_lib.c |  141 
  1 files changed, 94 insertions(+), 47 deletions(-)
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