[RFC PATCH v1] libcamera: pipeline: uvcvideo: Fix `ExposureTimeMode` control
Barnabás Pőcze
pobrn at protonmail.com
Wed Jan 29 13:13:12 CET 2025
Hi
2025. január 29., szerda 10:22 keltezéssel, Jacopo Mondi <jacopo.mondi at ideasonboard.com> írta:
> Hi Barnabás
>
> On Tue, Jan 28, 2025 at 12:14:01PM +0000, Barnabás Pőcze wrote:
> > `ControlInfo(Span<const int32_t>{...})` calls the incorrect constructor
> > of `ControlInfo`. The intended constructor to be called is
> > `ControlInfo(Span<const ControlValue>, ...)` however that is not called
> > because a span of `const int32_t` is passed. Instead, the constructor
> > `ControlInfo(const ControlValue &min, const ControlValue &max, ...)`
> > will be called.
> >
> > To fix this, simply pass a span of `ControlValue` instead.
> >
> > Furthermore, the mapping in `UVCCameraData::processControl()` is also not
> > entirely correct because the control value is retrieved as a `bool`
> > instead of - the correct type - `int32_t`. Additionally, the available
> > modes are not taken into account.
> >
> > To fix this, stores the available modes for `V4L2_CID_EXPOSURE_AUTO`
> > and select the appropriate mode based on the mapping established
> > in the comment.
> >
> > Fixes: bad8d591f8acfa ("libcamera: uvcvideo: Register ExposureTimeMode control")
> > Signed-off-by: Barnabás Pőcze <pobrn at protonmail.com>
> > ---
> > src/libcamera/pipeline/uvcvideo/uvcvideo.cpp | 81 +++++++++++++-------
> > 1 file changed, 53 insertions(+), 28 deletions(-)
> >
> > diff --git a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
> > index dedcac89b..7821cceb0 100644
> > --- a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
> > +++ b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
> > @@ -6,6 +6,7 @@
> > */
> >
> > #include <algorithm>
> > +#include <bitset>
> > #include <cmath>
> > #include <fstream>
> > #include <map>
> > @@ -58,6 +59,13 @@ public:
> > Stream stream_;
> > std::map<PixelFormat, std::vector<SizeRange>> formats_;
> >
> > + std::bitset<std::max({
> > + V4L2_EXPOSURE_AUTO,
> > + V4L2_EXPOSURE_MANUAL,
> > + V4L2_EXPOSURE_APERTURE_PRIORITY,
> > + V4L2_EXPOSURE_SHUTTER_PRIORITY,
> > + }) + 1> availableExposureModes_;
> > +
>
> I presume a bitset is used for efficiency ?
I suppose you could say that. I thought an `std::set` was a bit of an overkill.
>
>
> > private:
> > bool generateId();
> >
> > @@ -95,8 +103,8 @@ public:
> > bool match(DeviceEnumerator *enumerator) override;
> >
> > private:
> > - int processControl(ControlList *controls, unsigned int id,
> > - const ControlValue &value);
> > + int processControl(UVCCameraData *data, ControlList *controls,
> > + unsigned int id, const ControlValue &value);
> > int processControls(UVCCameraData *data, Request *request);
> >
> > bool acquireDevice(Camera *camera) override;
> > @@ -289,8 +297,8 @@ void PipelineHandlerUVC::stopDevice(Camera *camera)
> > data->video_->releaseBuffers();
> > }
> >
> > -int PipelineHandlerUVC::processControl(ControlList *controls, unsigned int id,
> > - const ControlValue &value)
> > +int PipelineHandlerUVC::processControl(UVCCameraData *data, ControlList *controls,
> > + unsigned int id, const ControlValue &value)
> > {
> > uint32_t cid;
> >
> > @@ -334,10 +342,27 @@ int PipelineHandlerUVC::processControl(ControlList *controls, unsigned int id,
> > }
> >
> > case V4L2_CID_EXPOSURE_AUTO: {
> > - int32_t ivalue = value.get<bool>()
> > - ? V4L2_EXPOSURE_APERTURE_PRIORITY
> > - : V4L2_EXPOSURE_MANUAL;
> > - controls->set(V4L2_CID_EXPOSURE_AUTO, ivalue);
> > + switch (value.get<int32_t>()) {
> > + case controls::ExposureTimeModeAuto:
> > + if (data->availableExposureModes_[V4L2_EXPOSURE_AUTO])
> > + controls->set(V4L2_CID_EXPOSURE_AUTO, V4L2_EXPOSURE_AUTO);
> > + else if (data->availableExposureModes_[V4L2_EXPOSURE_APERTURE_PRIORITY])
> > + controls->set(V4L2_CID_EXPOSURE_AUTO, V4L2_EXPOSURE_APERTURE_PRIORITY);
> > + else
> > + ASSERT(false);
> > + break;
> > + case controls::ExposureTimeModeManual:
> > + if (data->availableExposureModes_[V4L2_EXPOSURE_MANUAL])
> > + controls->set(V4L2_CID_EXPOSURE_AUTO, V4L2_EXPOSURE_MANUAL);
> > + else if (data->availableExposureModes_[V4L2_EXPOSURE_SHUTTER_PRIORITY])
> > + controls->set(V4L2_CID_EXPOSURE_AUTO, V4L2_EXPOSURE_SHUTTER_PRIORITY);
> > + else
> > + ASSERT(false);
> > + break;
> > + default:
> > + ASSERT(false);
> > + break;
> > + }
> > break;
> > }
> >
> > @@ -375,7 +400,7 @@ int PipelineHandlerUVC::processControls(UVCCameraData *data, Request *request)
> > ControlList controls(data->video_->controls());
> >
> > for (const auto &[id, value] : request->controls())
> > - processControl(&controls, id, value);
> > + processControl(data, &controls, id, value);
> >
> > for (const auto &ctrl : controls)
> > LOG(UVC, Debug)
> > @@ -725,25 +750,25 @@ void UVCCameraData::addControl(uint32_t cid, const ControlInfo &v4l2Info,
> > * ExposureTimeModeManual = { V4L2_EXPOSURE_MANUAL,
> > * V4L2_EXPOSURE_SHUTTER_PRIORITY }
> > */
> > - std::array<int32_t, 2> values{};
> > -
> > - auto it = std::find_if(v4l2Values.begin(), v4l2Values.end(),
> > - [&](const ControlValue &val) {
> > - return (val.get<int32_t>() == V4L2_EXPOSURE_APERTURE_PRIORITY ||
> > - val.get<int32_t>() == V4L2_EXPOSURE_AUTO) ? true : false;
> > - });
> > - if (it != v4l2Values.end())
> > - values.back() = static_cast<int32_t>(controls::ExposureTimeModeAuto);
> > -
> > - it = std::find_if(v4l2Values.begin(), v4l2Values.end(),
> > - [&](const ControlValue &val) {
> > - return (val.get<int32_t>() == V4L2_EXPOSURE_SHUTTER_PRIORITY ||
> > - val.get<int32_t>() == V4L2_EXPOSURE_MANUAL) ? true : false;
> > - });
> > - if (it != v4l2Values.end())
> > - values.back() = static_cast<int32_t>(controls::ExposureTimeModeManual);
> > -
> > - info = ControlInfo{Span<int32_t>{values}, values[0]};
> > + for (const ControlValue &value : v4l2Values) {
> > + auto x = value.get<int32_t>();
> > + if (0 <= x && size_t(x) < availableExposureModes_.size())
>
> Can x be negative ? It should come from enum v4l2_exposure_auto_type,
> doesn't it ?
Yes, it should, but I don't know if it will ever be extended or similar, so
doing the bounds checking seemed the most logical decision.
>
> Also, isn't size_t(x) == 4, why do you need to check it against the
> bitset size ?
I can't see why `x` would be 4. But `availableExposureModes_.size()` is 4.
>
> > + availableExposureModes_[x] = true;
> > + }
> > +
> > + std::array<ControlValue, 2> values;
> > + std::size_t count = 0;
> > +
> > + if (availableExposureModes_[V4L2_EXPOSURE_AUTO] || availableExposureModes_[V4L2_EXPOSURE_APERTURE_PRIORITY])
> > + values[count++] = controls::ExposureTimeModeAuto;
> > +
> > + if (availableExposureModes_[V4L2_EXPOSURE_MANUAL] || availableExposureModes_[V4L2_EXPOSURE_SHUTTER_PRIORITY])
> > + values[count++] = controls::ExposureTimeModeManual;
> > +
> > + if (count == 0)
> > + return;
> > +
> > + info = ControlInfo{Span<const ControlValue>{ values.data(), count }, values[0]};
> > break;
> > }
> > case V4L2_CID_EXPOSURE_ABSOLUTE:
> > --
> > 2.48.1
> >
> >
>
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