[alsa-devel] [ASoC] Missing shutdown() vectors in ASoC
nobin.mathew at gmail.com
Mon Jun 18 09:42:09 CEST 2007
Can you please look at this mail Thread.
On 6/12/07, Liam Girdwood <lg at opensource.wolfsonmicro.com> wrote:
> On Tue, 2007-06-12 at 17:44 +0530, Nobin Mathew wrote:
> > Liam
> > I am trying to implement shutdown in ASoC
> > /* dapm stream operations */
> > #define SND_SOC_DAPM_STREAM_NOP 0x0
> > #define SND_SOC_DAPM_STREAM_START 0x1
> > #define SND_SOC_DAPM_STREAM_STOP 0x2
> > #define SND_SOC_DAPM_STREAM_SUSPEND 0x4
> > #define SND_SOC_DAPM_STREAM_RESUME 0x8
> > #define SND_SOC_DAPM_STREAM_PAUSE_PUSH 0x10
> > #define SND_SOC_DAPM_STREAM_PAUSE_RELEASE 0x20
> > Is there any need to add stream operation called
> > SND_SOC_DAPM_STREAM_SHUTDOWN even though this has no effect no the
> > system behaviour.
> > Instead we can use SND_SOC_DAPM_STREAM_SUSPEND.
> > Is this OK.
> > is there any better way to implement suspend?, i think suspend will be
> > a copy of remove() function.
> I assume your looking to shutdown the codec to a low power state without
> removing the driver ?
> If so, SND_SOC_DAPM_STREAM_* operations all act upon stream and path
> based widgets (stream and path domain from soc-dapm.h). That is, they
> will always power up/down widgets that are actively used in the playback
> or capture of audio. This happens automatically at the end of
> playback/capture. The wont power down the codec domain.
> Atm, the codec power domain (VRef, Vmid) is only affected by signalling
> a dapm device event. This happens at probe/remove and suspend/resume atm
> for most codecs, although some codecs can alter their Vmid/Vref settings
> as part of stream/path domain power changes (as above, e.g. WM8753
> changes Vmid from 50k @ SNDRV_CTL_POWER_D0 to 500k SNDRV_CTL_POWER_D3)
> Fwiw, I've already added the shutdown function in the new ppc-dev
> branch. All component drivers will contain a struct device_driver and
> inherit it's features. More on this later today, for the moment the
> latest soc.h is here :-
> and pxa-i2s driver is here fyi :-
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