pcm: file: update linked hw_ptr and appl_ptr

Plugin file provides no private hw_ptr and appl_ptr but instead links
them to the slave pcm.  If the slave pcm itself changes its hw_ptr or
app_prt this needs to be done in file plugin, too.

Plugin 'plug' is such a candidate changing the hw_ptr and app_ptr in
hw_params call dependent on the automatically inserted plugins.  ALSA
unfortunately has no support for automatically updating chained
pointers.

A notification on pointer change seems to be prepared inside the
snd_pcm_set_ptr() routine via rbptr->changed(), but it is not (yet)
implemented so that we need to care for it manually.

Signed-off-by: Andreas Pape <apape@de.adit-jv.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/src/pcm/pcm_file.c b/src/pcm/pcm_file.c
index ae58c531360e35864c3898c750a6234609be1f7a..6d119d61f9bc9aa9014a28a20a11074965b35f95 100644 (file)
--- a/src/pcm/pcm_file.c
+++ b/src/pcm/pcm_file.c
@@ -642,6 +642,14 @@ static int snd_pcm_file_hw_params(snd_pcm_t *pcm, snd_pcm_hw_params_t * params)
                        return err;
                }
        }
+
+       /* pointer may have changed - e.g if plug is used. */
+       snd_pcm_unlink_hw_ptr(pcm, file->gen.slave);
+       snd_pcm_unlink_appl_ptr(pcm, file->gen.slave);
+
+       snd_pcm_link_hw_ptr(pcm, file->gen.slave);
+       snd_pcm_link_appl_ptr(pcm, file->gen.slave);
+
        return 0;
 }