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From:   "S.j. Wang" <shengjiu.wang@nxp.com>
To:     Mark Brown <broonie@kernel.org>
CC:     Nicolin Chen <nicoleotsuka@gmail.com>,
        "timur@kernel.org" <timur@kernel.org>,
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Subject: Re: [PATCH] ASoC: fsl_esai: Add pm runtime function
Thread-Topic: [PATCH] ASoC: fsl_esai: Add pm runtime function
Thread-Index: AdT115NXaHh4QUXfTQKmQnqsBIdDWA==
Date:   Thu, 18 Apr 2019 11:12:45 +0000
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Hi

> On Thu, Apr 18, 2019 at 10:15:24AM +0000, S.j. Wang wrote:
> > > On Thu, Apr 18, 2019 at 02:00:12AM -0700, Nicolin Chen wrote:
> > > > On Thu, Apr 18, 2019 at 03:29:09AM +0000, S.j. Wang wrote:
>=20
> > > > Just for curiosity, we had similar situation on imx6sx, so we
> > > > added suspend/resume with regcache. Why will the clock enable
> > > > state be lost too? Does CCM on imx8 (might not be called CCM
> > > > though) have any difference? What about clock rate settings?
>=20
> > > That sounds like a bug somewhere else - I'd expect that after resume
> > > the clocking would be restored to the state it was in before suspend.
>=20
> > There is limitation in our internal design. That is in imx8 the power
> > of subsystem will be disabled at suspend, include the clock state , clo=
ck
> rate.
>=20
> Right, that's fairly normal but usually it'd be restored as part of the r=
esume
> process?
>=20
> > This patch is to enable the pm runtime,  so I think it is better to
> > move the clock operation to pm runtime,  and close the clock at
> > suspend to reduce the power.
>=20
> It's definitely good to turn the clock off as much as possible, yes.

Thanks, will send v2.

Best regards
Wang shengjiu