Re: [PATCH alsa-lib 3/4] pcm: hw: introduce SNDRV_PCM_INFO_PERFECT_DRAIN

[Oswald Buddenhagen <oswald.buddenhagen@gmx.de>]

On Tue, May 02, 2023 at 01:50:09PM +0200, Jaroslav Kysela wrote:
>The driver may not require to touch the sample stream
>
"touching"

>for the drain operation at all.
>Handle this situation in alsa-lib.
>
this is weird without already knowing the context. i'd instead write:

   Handle the driver informing us that it is not necessary to set up 
   silencing upon playback draining. This will be the case for drivers 
   which are guaranteed to not read any samples beyond the application 
   pointer.

>--- a/src/pcm/pcm.c
>+++ b/src/pcm/pcm.c
>@@ -3707,6 +3707,29 @@ int snd_pcm_hw_params_can_disable_period_wakeup(const snd_pcm_hw_params_t *param
> 	return !!(params->info & SNDRV_PCM_INFO_NO_PERIOD_WAKEUP);
> }
> 
>+/**
>+ * \brief Check if hardware does perfect drain
>
"(is a) perfect drain" vs. "does draining".

>+ * \param params Configuration space
>+ * \retval 0 Hardware doesn't do perfect drain
>+ * \retval 1 Hardware does perfect drain
>+ *
>+ * This function should only be called when the configuration space
>
"should be called only when"

>+ * contains a single configuration. Call #snd_pcm_hw_params to choose
>+ * a single configuration from the configuration space.
>+ *
>+ * The perfect drain means that the hardware does not use samples
>
see above. i guess one way to write it here would be

   "Perfect drain" means [...]

>+ * beyond the stream application pointer.
>+ */

regards