The plug plugin copies the fast_ops structure and fast_op_arg from its slave PCM on initialization and after inserting a new plugin. This works unless the slave PCM is also an instance of the plug plugin because plug can change its fast_ops structure during _snd_pcm_hw_params.
Instead of copying fast_ops in snd_pcm_plug_insert_plugins wait until the end of snd_pcm_plug_hw_params when the slave has been fully initialized.
This fixes a crash when two instances of plug are instantiated back to back and the format conversion plugin inserted by the second is skipped by the first because the fast_ops pointer is not properly updated. This is the case for applications requesting plug:default on Intel HDA chips. --- src/pcm/pcm_plug.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/src/pcm/pcm_plug.c b/src/pcm/pcm_plug.c index e9d2923..72456d5 100644 --- a/src/pcm/pcm_plug.c +++ b/src/pcm/pcm_plug.c @@ -659,8 +659,6 @@ static int snd_pcm_plug_insert_plugins(snd_pcm_t *pcm, } if (err) { plug->gen.slave = new; - pcm->fast_ops = new->fast_ops; - pcm->fast_op_arg = new->fast_op_arg; } k++; } @@ -1049,6 +1047,9 @@ static int snd_pcm_plug_hw_params(snd_pcm_t *pcm, snd_pcm_hw_params_t *params) } snd_pcm_unlink_hw_ptr(pcm, plug->req_slave); snd_pcm_unlink_appl_ptr(pcm, plug->req_slave); + + pcm->fast_ops = slave->fast_ops; + pcm->fast_op_arg = slave->fast_op_arg; snd_pcm_link_hw_ptr(pcm, slave); snd_pcm_link_appl_ptr(pcm, slave); return 0;