[libcamera-devel] [PATCH] libcamera: ipa_proxy: Allow stop() on a stopped IPA

[Laurent Pinchart]

Hi Jacopo,

On Mon, Jul 06, 2020 at 01:49:13PM +0200, Jacopo Mondi wrote:
> On Mon, Jul 06, 2020 at 02:08:47PM +0300, Laurent Pinchart wrote:
> > To make error handling easier in callers, allow the stop() function to
> > be called when the proxy is already stopped, or not started yet.
> >
> > Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > ---
> >  include/libcamera/internal/ipa_proxy.h   |  2 ++
> >  src/libcamera/ipa_proxy.cpp              | 10 ++++++++++
> >  src/libcamera/proxy/ipa_proxy_thread.cpp |  3 +++
> >  3 files changed, 15 insertions(+)
> >
> > diff --git a/include/libcamera/internal/ipa_proxy.h b/include/libcamera/internal/ipa_proxy.h
> > index aec8f04ffc15..b429ce5a68a3 100644
> > --- a/include/libcamera/internal/ipa_proxy.h
> > +++ b/include/libcamera/internal/ipa_proxy.h
> > @@ -27,6 +27,8 @@ public:
> >
> >  	std::string configurationFile(const std::string &file) const;
> >
> > +	void stop() override = 0;
> > +
> >  protected:
> >  	std::string resolvePath(const std::string &file) const;
> >
> > diff --git a/src/libcamera/ipa_proxy.cpp b/src/libcamera/ipa_proxy.cpp
> > index 23be24ad9bf1..01740a6e39ec 100644
> > --- a/src/libcamera/ipa_proxy.cpp
> > +++ b/src/libcamera/ipa_proxy.cpp
> > @@ -145,6 +145,16 @@ std::string IPAProxy::configurationFile(const std::string &name) const
> >  	return std::string();
> >  }
> >
> > +/**
> > + * \fn IPAProxy::stop()
> > + * \brief Stop the IPA proxy
> > + *
> > + * This method informs the IPA module that the camera is stopped. The IPA module
> > + * shall release resources prepared in start(). Calling stop() when the IPA
> 
> s/prepared/acquired ?
> 
> > + * hasn't been started or has already been stopped is valid, and the IPA shall
> > + * treat this as a no-op.
> > + */
> > +
> >  /**
> >   * \brief Find a valid full path for a proxy worker for a given executable name
> >   * \param[in] file File name of proxy worker executable
> > diff --git a/src/libcamera/proxy/ipa_proxy_thread.cpp b/src/libcamera/proxy/ipa_proxy_thread.cpp
> > index aa403e22f297..eead2883708d 100644
> > --- a/src/libcamera/proxy/ipa_proxy_thread.cpp
> > +++ b/src/libcamera/proxy/ipa_proxy_thread.cpp
> > @@ -121,6 +121,9 @@ int IPAProxyThread::start()
> >
> >  void IPAProxyThread::stop()
> >  {
> > +	if (!running_)
> > +		return;
> > +
> 
> In case the IPA is then stopped already, IPA won't receive the call,
> making the above "hasn't been started or has already been stopped is
> valid" possibly confusing.

I agree with you. How about the following ?

 * This function stops the IPA and releases all the resources acquired by the
 * proxy in start(). Calling stop() when the IPA proxy hasn't been started or
 * has already been stopped is valid, the proxy shall treat this as a no-op and
 * shall not forward the call to the IPA.

> With out without these addressed
> Reviewed-by: Jacopo Mondi <jacopo at jmondi.org>
> 
> >  	running_ = false;
> >
> >  	proxy_.invokeMethod(&ThreadProxy::stop, ConnectionTypeBlocking);

-- 
Regards,

Laurent Pinchart