[v3,4/4] libcamera: pipeline: uvcvideo: Fix `ExposureTime` control handling
diff mbox series

Message ID 20250314174248.1015718-5-barnabas.pocze@ideasonboard.com
State New
Headers show
Series
  • libcamera: pipeline: uvcvideo: Fix `ExposureTimeMode` control
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Commit Message

Barnabás Pőcze March 14, 2025, 5:42 p.m. UTC
The documentation of `ExposureTime` states that its value is ignored if
`ExposureTimeMode` is not manual. This is currently not handled, and if
`ExposureTimeMode` is automatic and `ExposureTime` is set, then the
controls will be rejected, as expected.

Only try to set `V4L2_CID_EXPOSURE_ABSOLUTE` if the current exposure mode
is manual. To be able to handle requests that set both `ExposureTime{,Mode}`,
process `ExposureTimeMode` first directly in `processControls()`, and store
this new mode in a temporary location. Then have `processControl()` act on
this temporary state, and only persist the temporary state if `setControls()`
on the video device succeeds.

Bug: https://bugs.libcamera.org/show_bug.cgi?id=242
Signed-off-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>
---
 src/libcamera/pipeline/uvcvideo/uvcvideo.cpp | 52 ++++++++++++--------
 1 file changed, 31 insertions(+), 21 deletions(-)

Patch
diff mbox series

diff --git a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
index 7d882ebe1..22d286e49 100644
--- a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
+++ b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
@@ -108,7 +108,7 @@  public:
 	bool match(DeviceEnumerator *enumerator) override;
 
 private:
-	int processControl(const UVCCameraData *data, ControlList *controls,
+	int processControl(const UVCCameraData::State &state, ControlList *controls,
 			   unsigned int id, const ControlValue &value);
 	int processControls(UVCCameraData *data, Request *request);
 
@@ -333,7 +333,7 @@  void PipelineHandlerUVC::stopDevice(Camera *camera)
 	data->state_.reset();
 }
 
-int PipelineHandlerUVC::processControl(const UVCCameraData *data, ControlList *controls,
+int PipelineHandlerUVC::processControl(const UVCCameraData::State &state, ControlList *controls,
 				       unsigned int id, const ControlValue &value)
 {
 	uint32_t cid;
@@ -378,26 +378,13 @@  int PipelineHandlerUVC::processControl(const UVCCameraData *data, ControlList *c
 	}
 
 	case V4L2_CID_EXPOSURE_AUTO: {
-		std::optional<v4l2_exposure_auto_type> mode;
-
-		switch (value.get<int32_t>()) {
-		case controls::ExposureTimeModeAuto:
-			mode = data->autoExposureMode_;
-			break;
-		case controls::ExposureTimeModeManual:
-			mode = data->manualExposureMode_;
-			break;
-		}
-
-		if (!mode)
-			return -EINVAL;
-
-		controls->set(V4L2_CID_EXPOSURE_AUTO, static_cast<int32_t>(*mode));
+		/* Handled directly in `processControls()`. */
 		break;
 	}
 
 	case V4L2_CID_EXPOSURE_ABSOLUTE:
-		controls->set(cid, value.get<int32_t>() / 100);
+		if (state.exp == controls::ExposureTimeModeManual)
+			controls->set(cid, value.get<int32_t>() / 100);
 		break;
 
 	case V4L2_CID_CONTRAST:
@@ -428,9 +415,30 @@  int PipelineHandlerUVC::processControl(const UVCCameraData *data, ControlList *c
 int PipelineHandlerUVC::processControls(UVCCameraData *data, Request *request)
 {
 	ControlList controls(data->video_->controls());
+	const auto &reqControls = request->controls();
+	auto newState = data->state_;
+
+	if (const auto exp = reqControls.get(controls::ExposureTimeMode)) {
+		std::optional<v4l2_exposure_auto_type> mode;
 
-	for (const auto &[id, value] : request->controls())
-		processControl(data, &controls, id, value);
+		switch (*exp) {
+		case controls::ExposureTimeModeAuto:
+			mode = data->autoExposureMode_;
+			break;
+		case controls::ExposureTimeModeManual:
+			mode = data->manualExposureMode_;
+			break;
+		}
+
+		if (!mode)
+			return -EINVAL;
+
+		controls.set(V4L2_CID_EXPOSURE_AUTO, static_cast<int32_t>(*mode));
+		newState.exp = static_cast<controls::ExposureTimeModeEnum>(*exp);
+	}
+
+	for (const auto &[id, value] : reqControls)
+		processControl(newState, &controls, id, value);
 
 	for (const auto &ctrl : controls)
 		LOG(UVC, Debug)
@@ -443,7 +451,9 @@  int PipelineHandlerUVC::processControls(UVCCameraData *data, Request *request)
 		return ret < 0 ? ret : -EINVAL;
 	}
 
-	return ret;
+	data->state_ = newState;
+
+	return 0;
 }
 
 int PipelineHandlerUVC::queueRequestDevice(Camera *camera, Request *request)