[libcamera-devel] [RFC PATCH v2 3/5] libcamera: ipu3: Disable a sensor test pattern mode at initialization

[Hirokazu Honda]

Hi Jacopo,

On Tue, Jun 22, 2021 at 7:33 PM Jacopo Mondi <jacopo at jmondi.org> wrote:
>
> Hi Hiro,
>
> On Tue, Jun 22, 2021 at 11:36:52AM +0900, Hirokazu Honda wrote:
> > Turns off a sensor test pattern mode at the initialization of the
> > sensor. Without this, the camera sensor is configured with the last
> > test pattern mode that has been set.
> >
> > Signed-off-by: Hirokazu Honda <hiroh at chromium.org>
> > ---
> >  src/libcamera/pipeline/ipu3/cio2.cpp | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> >
> > diff --git a/src/libcamera/pipeline/ipu3/cio2.cpp b/src/libcamera/pipeline/ipu3/cio2.cpp
> > index 1be2cbcd..8548f749 100644
> > --- a/src/libcamera/pipeline/ipu3/cio2.cpp
> > +++ b/src/libcamera/pipeline/ipu3/cio2.cpp
> > @@ -9,6 +9,7 @@
> >
> >  #include <linux/media-bus-format.h>
> >
> > +#include <libcamera/control_ids.h>
> >  #include <libcamera/formats.h>
> >  #include <libcamera/geometry.h>
> >  #include <libcamera/stream.h>
> > @@ -192,6 +193,13 @@ int CIO2Device::configure(const Size &size, V4L2DeviceFormat *outputFormat)
> >
> >       LOG(IPU3, Debug) << "CIO2 output format " << outputFormat->toString();
> >
> > +     ret = sensor_->setTestPatternMode(controls::draft::TestPatternModeOff);
> > +     if (ret) {
> > +             LOG(IPU3, Error)
> > +                     << "Failed to reset test pattern mode: " << ret;
> > +             return ret;
> > +     }
> > +
>
> Now I see why you need all the checks in the previous patch. But, do
> we need to do so ? Isn't the application which is in control of the
> test pattern ? Shouldn't the app explicitly disable it if they want to
> ?
>

An application implementation is not controlled by us.
It can specify an invalid test pattern mode. I would like to have the guard.

> Shouldn't the app explicitly disable it if they want to

I am not sure honestly. I *think* most apps don't reset the test
pattern (i.e. disable) in either start up and termination, because a
v4l2 sensor driver resets the test pattern in open() or close().
But the libcamera implementation keeps opening the node and in
libcamera we should reset in configure().

-Hiro
> >       return 0;
> >  }
> >
> > --
> > 2.32.0.288.g62a8d224e6-goog
> >