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

[Laurent Pinchart]

Hi Hiro,

On Tue, May 25, 2021 at 02:35:17PM +0900, Hirokazu Honda wrote:
> On Tue, May 25, 2021 at 8:52 AM Laurent Pinchart 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/

Oops :-S We've received reports from users who are affected by this, so
I've sent a revert that I'll merge now, to be able to discuss the fix
without pressure.

> > > ---
> > >  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