[libcamera-devel] [PATCH v4 1/7] libcamera: delayed_controls: Add notion of priority write

Naushir Patuck naush at raspberrypi.com
Sat Mar 13 08:33:43 CET 2021


Hi Laurent,

On Fri, 12 Mar 2021, 8:57 pm Laurent Pinchart, <
laurent.pinchart at ideasonboard.com> wrote:

> Hi Naush,
>
> Thank you for the patch.
>
> On Thu, Mar 04, 2021 at 08:17:22AM +0000, Naushir Patuck wrote:
> > If an exposure time change adjusts the vblanking limits, and we set both
> > VBLANK and EXPOSURE controls through the VIDIOC_S_EXT_CTRLS ioctl, the
> > latter may fail if the value is outside of the limits calculated by the
> > old VBLANK value. This is a limitation in V4L2 and cannot be fixed by
> > setting VBLANK before EXPOSURE in a single VIDIOC_S_EXT_CTRLS ioctl.
> >
> > The workaround here is to have the DelayedControls object mark the
> > VBLANK control as "priority write", which then write VBLANK separately
> > from (and ahead of) any other controls. This way, the sensor driver will
> > update the EXPOSURE control with new limits before the new values is
> > presented, and will thus be seen as valid.
> >
> > To support this, a new struct DelayedControls::ControlParams is used in
> > the constructor to provide the control delay value as well as the
> > priority write flag.
> >
> > Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
> > Tested-by: David Plowman <david.plowman at raspberrypi.com>
> > Reviewed-by: Paul Elder <paul.elder at ideasonboard.com>
> > ---
> >  include/libcamera/internal/delayed_controls.h |  9 +++-
> >  src/libcamera/delayed_controls.cpp            | 54 +++++++++++++------
> >  src/libcamera/pipeline/ipu3/ipu3.cpp          |  8 +--
> >  .../pipeline/raspberrypi/raspberrypi.cpp      | 13 +++--
> >  src/libcamera/pipeline/rkisp1/rkisp1.cpp      |  8 +--
> >  test/delayed_contols.cpp                      | 20 +++----
> >  6 files changed, 68 insertions(+), 44 deletions(-)
> >
> > diff --git a/include/libcamera/internal/delayed_controls.h
> b/include/libcamera/internal/delayed_controls.h
> > index dc447a882514..564d9f2e2440 100644
> > --- a/include/libcamera/internal/delayed_controls.h
> > +++ b/include/libcamera/internal/delayed_controls.h
> > @@ -19,8 +19,13 @@ class V4L2Device;
> >  class DelayedControls
> >  {
> >  public:
> > +     struct ControlParams {
> > +             unsigned int delay;
> > +             bool priorityWrite;
> > +     };
>
> I've only noticed now that the series has been merged, this structure
> isn't documented:
>
> [333/464] Generating doxygen with a custom command
> include/libcamera/internal/delayed_controls.h:22: warning: Compound
> libcamera::DelayedControls::ControlParams is not documented.
> include/libcamera/internal/delayed_controls.h:23: warning: Member delay
> (variable) of struct libcamera::DelayedControls::ControlParams is not
> documented.
> include/libcamera/internal/delayed_controls.h:24: warning: Member
> priorityWrite (variable) of struct
> libcamera::DelayedControls::ControlParams is not documented.
>
> Could you send a follow-up patch to address this ?
>

Apologies for missing the doc update. I will post a patch with it soon.


> I'm also curious if I'm the only one compiling the documentation :-)
>

My documentation compilation is likely disabled, but I will switch it back
on now :-)

Regards,
Naush


> > +
> >       DelayedControls(V4L2Device *device,
> > -                     const std::unordered_map<uint32_t, unsigned int>
> &delays);
> > +                     const std::unordered_map<uint32_t, ControlParams>
> &controlParams);
> >
> >       void reset();
> >
> > @@ -64,7 +69,7 @@ private:
> >
> >       V4L2Device *device_;
> >       /* \todo Evaluate if we should index on ControlId * or unsigned
> int */
> > -     std::unordered_map<const ControlId *, unsigned int> delays_;
> > +     std::unordered_map<const ControlId *, ControlParams>
> controlParams_;
> >       unsigned int maxDelay_;
> >
> >       bool running_;
> > diff --git a/src/libcamera/delayed_controls.cpp
> b/src/libcamera/delayed_controls.cpp
> > index ab1d40057c5f..3ed1dfebd035 100644
> > --- a/src/libcamera/delayed_controls.cpp
> > +++ b/src/libcamera/delayed_controls.cpp
> > @@ -40,15 +40,19 @@ LOG_DEFINE_CATEGORY(DelayedControls)
> >  /**
> >   * \brief Construct a DelayedControls instance
> >   * \param[in] device The V4L2 device the controls have to be applied to
> > - * \param[in] delays Map of the numerical V4L2 control ids to their
> associated
> > - * delays (in frames)
> > + * \param[in] controlParams Map of the numerical V4L2 control ids to
> their
> > + * associated control parameters.
> >   *
> > - * Only controls specified in \a delays are handled. If it's desired to
> mix
> > - * delayed controls and controls that take effect immediately the
> immediate
> > - * controls must be listed in the \a delays map with a delay value of 0.
> > + * The control parameters comprise of delays (in frames) and a priority
> write
> > + * flag. If this flag is set, the relevant control is written
> separately from,
> > + * ahead of the reset of the batched controls.
> > + *
> > + * Only controls specified in \a controlParams are handled. If it's
> desired to
> > + * mix delayed controls and controls that take effect immediately the
> immediate
> > + * controls must be listed in the \a controlParams map with a delay
> value of 0.
> >   */
> >  DelayedControls::DelayedControls(V4L2Device *device,
> > -                              const std::unordered_map<uint32_t,
> unsigned int> &delays)
> > +                              const std::unordered_map<uint32_t,
> ControlParams> &controlParams)
> >       : device_(device), maxDelay_(0)
> >  {
> >       const ControlInfoMap &controls = device_->controls();
> > @@ -57,12 +61,12 @@ DelayedControls::DelayedControls(V4L2Device *device,
> >        * Create a map of control ids to delays for controls exposed by
> the
> >        * device.
> >        */
> > -     for (auto const &delay : delays) {
> > -             auto it = controls.find(delay.first);
> > +     for (auto const &param : controlParams) {
> > +             auto it = controls.find(param.first);
> >               if (it == controls.end()) {
> >                       LOG(DelayedControls, Error)
> >                               << "Delay request for control id "
> > -                             << utils::hex(delay.first)
> > +                             << utils::hex(param.first)
> >                               << " but control is not exposed by device "
> >                               << device_->deviceNode();
> >                       continue;
> > @@ -70,13 +74,14 @@ DelayedControls::DelayedControls(V4L2Device *device,
> >
> >               const ControlId *id = it->first;
> >
> > -             delays_[id] = delay.second;
> > +             controlParams_[id] = param.second;
> >
> >               LOG(DelayedControls, Debug)
> > -                     << "Set a delay of " << delays_[id]
> > +                     << "Set a delay of " << controlParams_[id].delay
> > +                     << " and priority write flag " <<
> controlParams_[id].priorityWrite
> >                       << " for " << id->name();
> >
> > -             maxDelay_ = std::max(maxDelay_, delays_[id]);
> > +             maxDelay_ = std::max(maxDelay_, controlParams_[id].delay);
> >       }
> >
> >       reset();
> > @@ -97,8 +102,8 @@ void DelayedControls::reset()
> >
> >       /* Retrieve control as reported by the device. */
> >       std::vector<uint32_t> ids;
> > -     for (auto const &delay : delays_)
> > -             ids.push_back(delay.first->id());
> > +     for (auto const &param : controlParams_)
> > +             ids.push_back(param.first->id());
> >
> >       ControlList controls = device_->getControls(ids);
> >
> > @@ -140,7 +145,7 @@ bool DelayedControls::push(const ControlList
> &controls)
> >
> >               const ControlId *id = it->second;
> >
> > -             if (delays_.find(id) == delays_.end())
> > +             if (controlParams_.find(id) == controlParams_.end())
> >                       return false;
> >
> >               Info &info = values_[id][queueCount_];
> > @@ -220,12 +225,27 @@ void DelayedControls::applyControls(uint32_t
> sequence)
> >       ControlList out(device_->controls());
> >       for (const auto &ctrl : values_) {
> >               const ControlId *id = ctrl.first;
> > -             unsigned int delayDiff = maxDelay_ - delays_[id];
> > +             unsigned int delayDiff = maxDelay_ -
> controlParams_[id].delay;
> >               unsigned int index = std::max<int>(0, writeCount_ -
> delayDiff);
> >               const Info &info = ctrl.second[index];
> >
> >               if (info.updated) {
> > -                     out.set(id->id(), info);
> > +                     if (controlParams_[id].priorityWrite) {
> > +                             /*
> > +                              * This control must be written now, it
> could
> > +                              * affect validity of the other controls.
> > +                              */
> > +                             ControlList priority(device_->controls());
> > +                             priority.set(id->id(), info);
> > +                             device_->setControls(&priority);
> > +                     } else {
> > +                             /*
> > +                              * Batch up the list of controls and write
> them
> > +                              * at the end of the function.
> > +                              */
> > +                             out.set(id->id(), info);
> > +                     }
> > +
> >                       LOG(DelayedControls, Debug)
> >                               << "Setting " << id->name()
> >                               << " to " << info.toString()
> > diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp
> b/src/libcamera/pipeline/ipu3/ipu3.cpp
> > index 3e6b88af4188..ac92f066a07e 100644
> > --- a/src/libcamera/pipeline/ipu3/ipu3.cpp
> > +++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
> > @@ -963,14 +963,14 @@ int PipelineHandlerIPU3::registerCameras()
> >                * a sensor database. For now use generic values taken from
> >                * the Raspberry Pi and listed as 'generic values'.
> >                */
> > -             std::unordered_map<uint32_t, unsigned int> delays = {
> > -                     { V4L2_CID_ANALOGUE_GAIN, 1 },
> > -                     { V4L2_CID_EXPOSURE, 2 },
> > +             std::unordered_map<uint32_t,
> DelayedControls::ControlParams> params = {
> > +                     { V4L2_CID_ANALOGUE_GAIN, { 1, false } },
> > +                     { V4L2_CID_EXPOSURE, { 2, false } },
> >               };
> >
> >               data->delayedCtrls_ =
> >
>  std::make_unique<DelayedControls>(cio2->sensor()->device(),
> > -                                                       delays);
> > +                                                       params);
> >               data->cio2_.frameStart().connect(data->delayedCtrls_.get(),
> >
> &DelayedControls::applyControls);
> >
> > diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> > index a60415d93705..ba74ace183db 100644
> > --- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> > +++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> > @@ -1244,16 +1244,15 @@ int RPiCameraData::configureIPA(const
> CameraConfiguration *config)
> >       if (result.params & ipa::RPi::ConfigSensorParams) {
> >               /*
> >                * Setup our delayed control writer with the sensor default
> > -              * gain and exposure delays.
> > +              * gain and exposure delays. Mark VBLANK for priority
> write.
> >                */
> > -             std::unordered_map<uint32_t, unsigned int> delays = {
> > -                     { V4L2_CID_ANALOGUE_GAIN,
> result.sensorConfig.gainDelay },
> > -                     { V4L2_CID_EXPOSURE,
> result.sensorConfig.exposureDelay },
> > -                     { V4L2_CID_VBLANK, result.sensorConfig.vblank }
> > +             std::unordered_map<uint32_t,
> DelayedControls::ControlParams> params = {
> > +                     { V4L2_CID_ANALOGUE_GAIN, {
> result.sensorConfig.gainDelay, false } },
> > +                     { V4L2_CID_EXPOSURE, {
> result.sensorConfig.exposureDelay, false } },
> > +                     { V4L2_CID_VBLANK, { result.sensorConfig.vblank,
> true } }
> >               };
> >
> > -             delayedCtrls_ =
> std::make_unique<DelayedControls>(unicam_[Unicam::Image].dev(), delays);
> > -
> > +             delayedCtrls_ =
> std::make_unique<DelayedControls>(unicam_[Unicam::Image].dev(), params);
> >               sensorMetadata_ = result.sensorConfig.sensorMetadata;
> >       }
> >
> > diff --git a/src/libcamera/pipeline/rkisp1/rkisp1.cpp
> b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
> > index a794501a9c8d..17c0f9751cd3 100644
> > --- a/src/libcamera/pipeline/rkisp1/rkisp1.cpp
> > +++ b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
> > @@ -938,14 +938,14 @@ int
> PipelineHandlerRkISP1::createCamera(MediaEntity *sensor)
> >        * a sensor database. For now use generic values taken from
> >        * the Raspberry Pi and listed as generic values.
> >        */
> > -     std::unordered_map<uint32_t, unsigned int> delays = {
> > -             { V4L2_CID_ANALOGUE_GAIN, 1 },
> > -             { V4L2_CID_EXPOSURE, 2 },
> > +     std::unordered_map<uint32_t, DelayedControls::ControlParams>
> params = {
> > +             { V4L2_CID_ANALOGUE_GAIN, { 1, false } },
> > +             { V4L2_CID_EXPOSURE, { 2, false } },
> >       };
> >
> >       data->delayedCtrls_ =
> >               std::make_unique<DelayedControls>(data->sensor_->device(),
> > -                                               delays);
> > +                                               params);
> >       isp_->frameStart.connect(data->delayedCtrls_.get(),
> >                                &DelayedControls::applyControls);
> >
> > diff --git a/test/delayed_contols.cpp b/test/delayed_contols.cpp
> > index 50169b12e566..3855eb18ecd4 100644
> > --- a/test/delayed_contols.cpp
> > +++ b/test/delayed_contols.cpp
> > @@ -72,8 +72,8 @@ protected:
> >
> >       int singleControlNoDelay()
> >       {
> > -             std::unordered_map<uint32_t, unsigned int> delays = {
> > -                     { V4L2_CID_BRIGHTNESS, 0 },
> > +             std::unordered_map<uint32_t,
> DelayedControls::ControlParams> delays = {
> > +                     { V4L2_CID_BRIGHTNESS, { 0, false } },
> >               };
> >               std::unique_ptr<DelayedControls> delayed =
> >                       std::make_unique<DelayedControls>(dev_.get(),
> delays);
> > @@ -109,8 +109,8 @@ protected:
> >
> >       int singleControlWithDelay()
> >       {
> > -             std::unordered_map<uint32_t, unsigned int> delays = {
> > -                     { V4L2_CID_BRIGHTNESS, 1 },
> > +             std::unordered_map<uint32_t,
> DelayedControls::ControlParams> delays = {
> > +                     { V4L2_CID_BRIGHTNESS, { 1, false } },
> >               };
> >               std::unique_ptr<DelayedControls> delayed =
> >                       std::make_unique<DelayedControls>(dev_.get(),
> delays);
> > @@ -150,9 +150,9 @@ protected:
> >
> >       int dualControlsWithDelay(uint32_t startOffset)
> >       {
> > -             std::unordered_map<uint32_t, unsigned int> delays = {
> > -                     { V4L2_CID_BRIGHTNESS, 1 },
> > -                     { V4L2_CID_CONTRAST, 2 },
> > +             std::unordered_map<uint32_t,
> DelayedControls::ControlParams> delays = {
> > +                     { V4L2_CID_BRIGHTNESS, { 1, false } },
> > +                     { V4L2_CID_CONTRAST, { 2, false } },
> >               };
> >               std::unique_ptr<DelayedControls> delayed =
> >                       std::make_unique<DelayedControls>(dev_.get(),
> delays);
> > @@ -197,9 +197,9 @@ protected:
> >
> >       int dualControlsMultiQueue()
> >       {
> > -             std::unordered_map<uint32_t, unsigned int> delays = {
> > -                     { V4L2_CID_BRIGHTNESS, 1 },
> > -                     { V4L2_CID_CONTRAST, 2 },
> > +             std::unordered_map<uint32_t,
> DelayedControls::ControlParams> delays = {
> > +                     { V4L2_CID_BRIGHTNESS, { 1, false } },
> > +                     { V4L2_CID_CONTRAST, { 2, false } }
> >               };
> >               std::unique_ptr<DelayedControls> delayed =
> >                       std::make_unique<DelayedControls>(dev_.get(),
> delays);
>
> --
> Regards,
>
> Laurent Pinchart
>
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