[libcamera-devel] [PATCH] libcamera: V4L2Device: Remove the controls order assumption in updateControls()

[Hirokazu Honda]

Hi Laurent,

On Tue, May 25, 2021 at 8:52 AM Laurent Pinchart <
laurent.pinchart at ideasonboard.com> wrote:

> Hi Hiro,
>
> Thank you for the patch. I'm going through the patchwork backlog and
> realized I had forgotten about this one. Sorry about that.
>
> On Tue, Apr 27, 2021 at 10:21:50AM +0900, Hirokazu Honda wrote:
> > The original updateControls() has the assumption that ctrls and
> > v4l2Ctrls lists are in the same order. It is dependent on the
> > caller implementation though. This changes updateControls()
> > implementation so that it works without the assumption.
> >
> > Signed-off-by: Hirokazu Honda <hiroh at chromium.org>
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
>
> Will push shortly once the tests pass.
>
>
I am sorry I noticed the patch has a bug. Somehow I haven't caught it.
I submit a fix patch for review.
https://patchwork.libcamera.org/patch/12396/

-Hiro


> > ---
> >  src/libcamera/v4l2_device.cpp | 26 +++++++-------------------
> >  1 file changed, 7 insertions(+), 19 deletions(-)
> >
> > diff --git a/src/libcamera/v4l2_device.cpp
> b/src/libcamera/v4l2_device.cpp
> > index 397029ac..64501523 100644
> > --- a/src/libcamera/v4l2_device.cpp
> > +++ b/src/libcamera/v4l2_device.cpp
> > @@ -178,12 +178,6 @@ ControlList V4L2Device::getControls(const
> std::vector<uint32_t> &ids)
> >
> >       ControlList ctrls{ controls_ };
> >
> > -     /*
> > -      * Start by filling the ControlList. This can't be combined with
> filling
> > -      * v4l2Ctrls, as updateControls() relies on both containers having
> the
> > -      * same order, and the control list is based on a map, which is not
> > -      * sorted by insertion order.
> > -      */
> >       for (uint32_t id : ids) {
> >               const auto iter = controls_.find(id);
> >               if (iter == controls_.end()) {
> > @@ -520,19 +514,13 @@ void V4L2Device::listControls()
> >  void V4L2Device::updateControls(ControlList *ctrls,
> >                               Span<const v4l2_ext_control> v4l2Ctrls)
> >  {
> > -     unsigned int i = 0;
> > -     for (auto &ctrl : *ctrls) {
> > -             if (i == v4l2Ctrls.size())
> > -                     break;
> > +     for (const v4l2_ext_control &v4l2Ctrl : v4l2Ctrls) {
> > +             const unsigned int id = v4l2Ctrl.id;
> >
> > -             const struct v4l2_ext_control *v4l2Ctrl = &v4l2Ctrls[i];
> > -             unsigned int id = ctrl.first;
> > -             ControlValue &value = ctrl.second;
> > -
> > -             const auto iter = controls_.find(id);
> > -             switch (iter->first->type()) {
> > +             ControlValue value = ctrls->get(id);
> > +             switch (value.type()) {
> >               case ControlTypeInteger64:
> > -                     value.set<int64_t>(v4l2Ctrl->value64);
> > +                     value.set<int64_t>(v4l2Ctrl.value64);
> >                       break;
> >
> >               case ControlTypeByte:
> > @@ -547,11 +535,11 @@ void V4L2Device::updateControls(ControlList *ctrls,
> >                        * \todo To be changed when support for string
> controls
> >                        * will be added.
> >                        */
> > -                     value.set<int32_t>(v4l2Ctrl->value);
> > +                     value.set<int32_t>(v4l2Ctrl.value);
> >                       break;
> >               }
> >
> > -             i++;
> > +             ctrls->set(id, value);
> >       }
> >  }
> >
>
> --
> Regards,
>
> Laurent Pinchart
>
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