[libcamera-devel] [PATCH v6 5/5] android: soraka: Add camera HAL configuration

[Jacopo Mondi]

Hello,

On Fri, Apr 16, 2021 at 10:21:52AM +0200, Jacopo Mondi wrote:
> Hello,
>
> On Thu, Apr 15, 2021 at 10:05:40PM +0300, Laurent Pinchart wrote:
> > Hi Tomasz,
> >
> > On Fri, Apr 16, 2021 at 01:08:47AM +0900, Tomasz Figa wrote:
> > > On Thu, Apr 15, 2021 at 10:56 PM Jacopo Mondi <jacopo at jmondi.org> wrote:
> > > > On Thu, Apr 15, 2021 at 03:52:13PM +0200, Jacopo Mondi wrote:
> > > > > Add camera HAL configuration file for IPU3 Soraka.
> > > >
> > > > I've sent this patch for discussion, but I'm wondering if libcamera is
> > > > the right place where to store the HAL configuration file.
> > > >
> > > > In my opinion they would be better placed in the device overlay, like
> > > > it happens today, in example, with the Intel HAL .xml configuration
> > > > files.
> > > >
> > > > What do you think ?
> > >
> > > How about non-Chrome OS users of the device? I think we should have a
> > > repository of default configuration files for supported devices, which
> > > would be used if there is no custom configuration provided.
>
> Remember the configuration file is a requirement only for the
> consumers of the Camera HAL. libcamera does not generically require
> that.
>
> >
> > I don't really foresee system integrators actively contributing to such
> > a repository, so this effort may be doomed from the very beginning :-S
> > We could have some sort of community-driven repository, but even in that
> > case, how would we get the right configuration file installed
> > automatically ?
> >
>
> I think the last question is the most relevant one. We can keep a
> repository somewhere of known configuration file, but which one has to
> be selected and installed it's not something that should be handled
> by the libcamera build system, as I assume we don't want to add
> device-specific steps to the build process. I would rather expect that
> system integrators that use libcamera have instead the target device
> as a very well defined concept in their build infrastructure, and they
> can easily support installing the right configuration file depending
> on the target.
>
> Although, I understand someone trying to integrate the camera HAL in
> their device might find the configuration file presence being a hard
> requirement a bit harsh, and might want some examples and a
> documentation of the expected formats (or better a schema) in the code
> base to build on top.
>
> > Distributing the configuration files as part of the system integration
> > seems better for Chrome OS. It may be a bit painful until the
> > configuration file format stabilizes though, so I'm not completely
> > opposed to carrying those files in the libcamera tree in the short term,
> > but we need to figure out a long term solution.
> >
> > Even if we carry those files in the libcamera source tree for now, how
> > do we ensure that the correct file gets installed in Chrome OS ?

I feel this is the last topic we need to solve to have the
configuration file series merged...

The question is: where do we collect and how to deploy the
configuration files ?

Not to re-state what said above, I don't mean to be pushy just to
summarize the situation a bit:

- configuration file is only used by the HAL
- libcamera does not have device-specific installation step
- vendors will likely not contribute much to any repository of
  configuration file, but rather prepare them ad-hoc for each device
- an example configuration file in the libcamera repository might be
  helpfull

All in all, I feel the distribution of configuration file is better
handled at the operating system level, and not directly by libcamera,
like it is done nowadays for the .xml tuning files for the
Intel/Rockchip HALs.

If we have an agreement on this, what is the plan to support
configuration files integration in ChromiumOS ?

Thanks
  j


> >
> > > > We should find a way to install this file in
> > > > /etc/libcamera/ before merging the series, otherwise we'll break the
> > > > HAL support in ChromiumOS.
> > > >
> > > > > Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > > > > Reviewed-by: Hirokazu Honda <hiroh at chromium.org>
> > > > > Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
> > > > > ---
> > > > >  src/android/data/soraka/camera_hal.yaml | 8 ++++++++
> > > > >  1 file changed, 8 insertions(+)
> > > > >  create mode 100644 src/android/data/soraka/camera_hal.yaml
> > > > >
> > > > > diff --git a/src/android/data/soraka/camera_hal.yaml b/src/android/data/soraka/camera_hal.yaml
> > > > > new file mode 100644
> > > > > index 000000000000..2e9964035098
> > > > > --- /dev/null
> > > > > +++ b/src/android/data/soraka/camera_hal.yaml
> > > > > @@ -0,0 +1,8 @@
> > > > > +cameras:
> > > > > +  "\\_SB_.PCI0.I2C4.CAM1":
> > > > > +    location: front
> > > > > +    rotation: 0
> > > > > +
> > > > > +  "\\_SB_.PCI0.I2C2.CAM0":
> > > > > +    location: back
> > > > > +    rotation: 0
> >
> > --
> > Regards,
> >
> > Laurent Pinchart
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