Re: [PATCH v8 09/24] ASoC: qdsp6: q6afe: Add q6afe driver

[Srinivas Kandagatla]

On 17/05/18 18:23, Mark Brown wrote:
> On Thu, May 17, 2018 at 06:10:49PM +0100, Srinivas Kandagatla wrote:
> > On 17/05/18 07:55, Mark Brown wrote:
> > > On Wed, May 09, 2018 at 01:56:20PM +0100, Srinivas Kandagatla wrote:
>
> > > This lock only protects the list, it does nothing to ensure that the
> > > port we look up is still valid by the time we return to the caller.
> > > That means we won't crash during list traversal but does nothing to
> > > ensure we won't crash immediately afterwards if the port is deallocated
> > > just after we look it up.  What stops that happening?
>
> > Each port is allocated and de-allocated in dai probe and remove calls
> > respectively.
>
> > Lets say... So for this case to happen the dai has to be removed (unload
> > module) at the same time when the interrupt callback happens due to delayed
> > response from previous commands.
>
> > This case would be almost impossible because all the calls to afe service
> > are synchronous with timeouts, if any of the previous calls times out the
> > respective caller would get an error, this should prevent him from unloading
> > the module in the first place.
>
> The user can also trigger manual unbinds without unloading the module,
> and to be honet the scenario where the DSP has stopped responding well
> and is delaying responses sounds like exactly the sort of time when
> users might try to reload the driver...Yes, that is one possible usecase!
ref-counting port should stop that from happening.
I will add this in next spin!

thanks,
srini