@@ -555,11 +555,35 @@ static int snd_pcm_hw_params_choose(struct snd_pcm_substream *pcm,
const int *v;
int err;
+ struct snd_interval __maybe_unused old_interval;
+ struct snd_mask __maybe_unused old_mask;
+
for (v = vars; *v != -1; v++) {
+ /* Keep old parameter to trace. */
+ if (trace_hw_params_mask_enabled()) {
+ if (hw_is_mask(*v))
+ old_mask = *hw_param_mask(params, *v);
+ }
+ if (trace_hw_params_interval_enabled()) {
+ if (hw_is_interval(*v))
+ old_interval = *hw_param_interval(params, *v);
+ }
+
if (*v != SNDRV_PCM_HW_PARAM_BUFFER_SIZE)
err = snd_pcm_hw_param_first(pcm, params, *v, NULL);
else
err = snd_pcm_hw_param_last(pcm, params, *v, NULL);
+
+ /* Trace the parameter. */
+ if (hw_is_mask(*v)) {
+ trace_hw_params_mask(pcm, *v, -1, &old_mask,
+ hw_param_mask(params, *v));
+ }
+ if (hw_is_interval(*v)) {
+ trace_hw_params_interval(pcm, *v, -1, &old_interval,
+ hw_param_interval(params, *v));
+ }
+
if (snd_BUG_ON(err < 0))
return err;
}
Results of ioctl(2) with SNDRV_PCM_IOCTL_HW_REFINE and SNDRV_PCM_IOCTL_HW_PARAMS are different, because the latter has single value for several parameters; e.g. channels of PCM substream. Selection of the single value is done independently of application of constraints and rules. It's helpful for developers to trace the selection process This commit adds tracepoints to snd_pcm_hw_params_choose() for the purpose. Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> --- sound/core/pcm_native.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+)