Alsa triggering methods

Alsa triggering methods

[Andy Ng]

Hi,

I am working on a ALSA card driver that handles a DSP instance. The
problem I have is that the triggering mechanism in ALSA to start a PCM
has the interrupts disabled, and my dsp framework is actually
acknowledging the start trigger with an event after 50 microseconds
time that I can't handle because the IRQs are disabled.

Is there any way when the trigger mechanism goes down to the card to
be able to handle any acknowledgements what will happen within a sort
period of time.

I have seen bespoke triggering method but not sure if everyone is using it.

Any ideas would be helpful.

Best regards,
Andreas

Re: Alsa triggering methods

[Vinod Koul]

On Wed, Apr 29, 2015 at 04:24:09PM +0100, Andy Ng wrote:
> Hi,
> 
> I am working on a ALSA card driver that handles a DSP instance. The
> problem I have is that the triggering mechanism in ALSA to start a PCM
> has the interrupts disabled, and my dsp framework is actually
> acknowledging the start trigger with an event after 50 microseconds
> time that I can't handle because the IRQs are disabled.
> 
> Is there any way when the trigger mechanism goes down to the card to
> be able to handle any acknowledgements what will happen within a sort
> period of time.
> 
> I have seen bespoke triggering method but not sure if everyone is using it.
> 
> Any ideas would be helpful.
trigger can be nonatomic too, you can set nonatomic = true for your pcms

-- 
~Vinod

Re: Alsa triggering methods

[Clemens Ladisch]

Andy Ng wrote:
> I am working on a ALSA card driver that handles a DSP instance. The
> problem I have is that the triggering mechanism in ALSA to start a PCM
> has the interrupts disabled, and my dsp framework is actually
> acknowledging the start trigger with an event after 50 microseconds
> time that I can't handle because the IRQs are disabled.

Why must you handle the ACK interrupt from inside the trigger?


Regards,
Clemens