Messages in this thread | | | Date | Mon, 21 Jul 2014 11:04:56 +0200 | From | Takashi Iwai <> | Subject | Re: [PATCH] ASoC: arizona: Disable AIF TX/RX before configuring it |
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At Mon, 21 Jul 2014 10:01:22 +0100, Richard Fitzgerald wrote: > > On Thu, Jul 17, 2014 at 08:42:15PM +0100, Mark Brown wrote: > > On Wed, Jul 16, 2014 at 01:10:39PM +0100, Richard Fitzgerald wrote: > > > > > If we don't disable the AIF TX/RX then we may fall into a > > > situation where the new AIF settings are ignored by the device. > > > For example, this problem manifests when switching between > > > different sample rates. > > > > So, what this does is momentarily disable the AIF when reconfiguring. > > That will glitch any running audio, making me wonder if the driver > > shouldn't be returning an error or at least complaining if it has to > > reconfigure instead. What's the use case where this might get > > triggered? > > The case being fixed is like this: > > aplay 48kHz.wav; aplay 96kHz.wav > > The second open happens before pmdown_time so the AIF is still enabled. > Writes to the AIF config registers only take effect if the AIF is disabled. > Without this patch, the 96kHz.wav will play at 48kHz
If the glitch really matters, the driver can minimize by checking the change of sample rate and doing temporary turn on/off only when required.
Takashi
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