[libcamera-devel] [PATCH] libcamera: v4l2_subdevice: Silence warning for unknown metadata formats

[Laurent Pinchart]

Commit e297673e7686 ("libcamera: v4l2_device: Adjust colorspace based on
pixel format") has introduced a warning when trying to convert a color
space from V4L2 to libcamera if the media bus code is unknown. This was
meant to catch unknown image formats, but turned out to be also
triggered for metadata formats.

Color spaces are not applicable to metadata formats, there should thus
be no warning. Fix it by skipping the color space translation and
returning std::nullopt directly if the kernel reports
V4L2_COLORSPACE_DEFAULT. This doesn't introduce any change in behaviour
other than getting rid of the warning, as the V4L2Device::toColorSpace()
function returns std::nullopt alread in that case.

Fixes: e297673e7686 ("libcamera: v4l2_device: Adjust colorspace based on pixel format")
Reported-by: Naushir Patuck <naush at raspberrypi.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
 include/libcamera/internal/v4l2_subdevice.h |  3 ++
 src/libcamera/v4l2_subdevice.cpp            | 51 ++++++++++-----------
 2 files changed, 26 insertions(+), 28 deletions(-)

diff --git a/include/libcamera/internal/v4l2_subdevice.h b/include/libcamera/internal/v4l2_subdevice.h
index 00be17bb1465..69862de0585a 100644
--- a/include/libcamera/internal/v4l2_subdevice.h
+++ b/include/libcamera/internal/v4l2_subdevice.h
@@ -101,6 +101,9 @@ protected:
 private:
 	LIBCAMERA_DISABLE_COPY(V4L2Subdevice)
 
+	std::optional<ColorSpace>
+	toColorSpace(const v4l2_mbus_framefmt &format) const;
+
 	std::vector<unsigned int> enumPadCodes(unsigned int pad);
 	std::vector<SizeRange> enumPadSizes(unsigned int pad,
 					    unsigned int code);
diff --git a/src/libcamera/v4l2_subdevice.cpp b/src/libcamera/v4l2_subdevice.cpp
index 95bfde340d8c..f3a9a0096c6c 100644
--- a/src/libcamera/v4l2_subdevice.cpp
+++ b/src/libcamera/v4l2_subdevice.cpp
@@ -477,6 +477,27 @@ V4L2Subdevice::Formats V4L2Subdevice::formats(unsigned int pad)
 	return formats;
 }
 
+std::optional<ColorSpace> V4L2Subdevice::toColorSpace(const v4l2_mbus_framefmt &format) const
+{
+	if (format.colorspace == V4L2_COLORSPACE_DEFAULT)
+		return std::nullopt;
+
+	PixelFormatInfo::ColourEncoding colourEncoding;
+	auto iter = formatInfoMap.find(format.code);
+	if (iter != formatInfoMap.end()) {
+		colourEncoding = iter->second.colourEncoding;
+	} else {
+		LOG(V4L2, Warning)
+			<< "Unknown subdev format "
+			<< utils::hex(format.code, 4)
+			<< ", defaulting to RGB encoding";
+
+		colourEncoding = PixelFormatInfo::ColourEncodingRGB;
+	}
+
+	return V4L2Device::toColorSpace(format, colourEncoding);
+}
+
 /**
  * \brief Retrieve the image format set on one of the V4L2 subdevice pads
  * \param[in] pad The 0-indexed pad number the format is to be retrieved from
@@ -503,20 +524,7 @@ int V4L2Subdevice::getFormat(unsigned int pad, V4L2SubdeviceFormat *format,
 	format->size.width = subdevFmt.format.width;
 	format->size.height = subdevFmt.format.height;
 	format->mbus_code = subdevFmt.format.code;
-
-	PixelFormatInfo::ColourEncoding colourEncoding;
-	auto iter = formatInfoMap.find(subdevFmt.format.code);
-	if (iter != formatInfoMap.end()) {
-		colourEncoding = iter->second.colourEncoding;
-	} else {
-		LOG(V4L2, Warning)
-			<< "Unknown subdev format "
-			<< utils::hex(subdevFmt.format.code, 4)
-			<< ", defaulting to RGB encoding";
-
-		colourEncoding = PixelFormatInfo::ColourEncodingRGB;
-	}
-	format->colorSpace = toColorSpace(subdevFmt.format, colourEncoding);
+	format->colorSpace = toColorSpace(subdevFmt.format);
 
 	return 0;
 }
@@ -562,20 +570,7 @@ int V4L2Subdevice::setFormat(unsigned int pad, V4L2SubdeviceFormat *format,
 	format->size.width = subdevFmt.format.width;
 	format->size.height = subdevFmt.format.height;
 	format->mbus_code = subdevFmt.format.code;
-
-	PixelFormatInfo::ColourEncoding colourEncoding;
-	auto iter = formatInfoMap.find(subdevFmt.format.code);
-	if (iter != formatInfoMap.end()) {
-		colourEncoding = iter->second.colourEncoding;
-	} else {
-		LOG(V4L2, Warning)
-			<< "Unknown subdev format "
-			<< utils::hex(subdevFmt.format.code, 4)
-			<< ", defaulting to RGB encoding";
-
-		colourEncoding = PixelFormatInfo::ColourEncodingRGB;
-	}
-	format->colorSpace = toColorSpace(subdevFmt.format, colourEncoding);
+	format->colorSpace = toColorSpace(subdevFmt.format);
 
 	return 0;
 }

base-commit: da9bb8dea6821edcfd3464e8cba37ad4a91087d6
-- 
Regards,

Laurent Pinchart