On Tue, Mar 14, 2023 at 6:14 PM Pierre-Louis Bossart
<pierre-louis.bossart@xxxxxxxxxxxxxxx> wrote:
>
>
>
> On 3/14/23 10:34, Daniel Baluta wrote:
> > From: Daniel Baluta <daniel.baluta@xxxxxxx>
> >
> > After commit bbf7d3b1c4f40 ("ASoC: soc-pcm: align BE 'atomicity' with
> > that of the FE") BE and FE atomicity must match.
> >
> > In the case of Compress PCM there is a mismatch in atomicity between FE
> > and BE and we get errors like this:
> >
> > [ 36.434566] sai1-wm8960-hifi: dpcm_be_connect: FE is atomic but BE
> > is nonatomic, invalid configuration
>
> Not clear on the 'FE is atomic' in the case of a compressed stream,
> which has to be handled with some sort of IPC, i.e. be nonatomic.
>
'FE is atomic' in this message is printed because this is the default value
of nonatomic field when PCM struct associated for a Compress PCM
struct is allocated.
No one changes 'nonatomic' field for Compress FE until my current patch.
> Also not sure why the FE is not set as nonatomic by the SOF parts?
> If it's needed for PCM, why wouldn't it be needed for compressed data?
FE is not touched for SOF parts. Only BE is set to nonatomic by SOF.
See: sound/soc/topology.c
» /* Set nonatomic property for FE dai links as their trigger
action involves IPC's */
» if (!link->no_pcm) {
» » link->nonatomic = true;
» » return 0;
» }
FE for PCM is modified by sound/soc/soc-pcm.c
int soc_new_pcm(struct snd_soc_pcm_runtime *rtd, int num)
» pcm->nonatomic = rtd->dai_link->nonatomic;
So, I guess people assumed that is enough to use RTD dai link to set
pcm->noatomic field
and didn't look at it in SOF.
When FE for Compress PCM is created, we don't use soc_new_pcm but instead
we use snd_pcm_new_internal which doesn't inherit the nonatomic field
of the rtd->dai_link
as Normal PCM does inside soc_pcm_new.
So, my patch makes sure we inherit the nonatomic field from
rtd->dai_link also for Compress PCM
similar with what already happens for Normal PCM.
tl;dr: when creating a Normal PCM pcm->nonatomic is inherited from RTD
DAI link. when creating a
Compress PCM pcm->nonatomic field is not set. This patch makes sure
that for Compres PCM
we also inherit nonatomic from RTD DAI link.
thanks,
Daniel.
