Re: [alsa-devel] [PATCH] ASoC: fsl_esai: Add pm runtime function
Hi
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:
In imx8 when systerm enter suspend state, the power of subsystem will be off, the clock enable state will be lost and register configuration
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?
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.
There is limitation in our internal design. That is in imx8 the power of subsystem will be disabled at suspend, include the clock state , clock rate.
I should not add it in comments, please ignore them, I will change the description.
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.
Best regards Wang shengjiu
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:
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?
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.
There is limitation in our internal design. That is in imx8 the power of subsystem will be disabled at suspend, include the clock state , clock rate.
Right, that's fairly normal but usually it'd be restored as part of the resume process?
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.
It's definitely good to turn the clock off as much as possible, yes.
participants (2)
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Mark Brown -
S.j. Wang