libcamera: v4l2_videodevice: Use bufferType_ in [get|try|set]Format()

V4L2VideoDevice is using the caps to determine which kind of buffers to
use with the video-device in 2 different cases:

1. V4L2VideoDevice::open()
2. V4L2VideoDevice::[get|try|set]Format()

And the order in which the caps are checked is different between
these 2 cases. This is a problem for /dev/video# nodes which support
both video-capture and metadata buffers. open() sets bufferType_ to
V4L2_BUF_TYPE_VIDEO_CAPTURE[_MPLANE] in this case, where as
[get|try|set]Format() will call [get|set]FormatMeta() which does not
work with V4L2_BUF_TYPE_VIDEO_CAPTURE[_MPLANE] buffers.

Switch [get|try|set]Format() to use the bufferType_ to determine on what
sort of buffers they should be operating, leaving the V4L2VideoDevice
code with only a single place where the decision is made what sort
of buffers it should operate on for a specific /dev/video# node.

This will also allow to modify open() in the future to take a bufferType
argument to allow overriding the default bufferType it selects for
/dev/video# nodes which are capable of supporting more then 1 buffer type.

Signed-off-by: Hans de Goede <[email protected]>
Reviewed-by: Jacopo Mondi <[email protected]>
Reviewed-by: Laurent Pinchart <[email protected]>
Signed-off-by: Laurent Pinchart <[email protected]>

src/libcamera/v4l2_videodevice.cpp

@@ -803,12 +803,19 @@ std::string V4L2VideoDevice::logPrefix() const
  */
 int V4L2VideoDevice::getFormat(V4L2DeviceFormat *format)
 {
-	if (caps_.isMeta())
-		return getFormatMeta(format);
-	else if (caps_.isMultiplanar())
-		return getFormatMultiplane(format);
-	else
+	switch (bufferType_) {
+	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
+	case V4L2_BUF_TYPE_VIDEO_OUTPUT:
 		return getFormatSingleplane(format);
+	case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
+	case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
+		return getFormatMultiplane(format);
+	case V4L2_BUF_TYPE_META_CAPTURE:
+	case V4L2_BUF_TYPE_META_OUTPUT:
+		return getFormatMeta(format);
+	default:
+		return -EINVAL;
+	}
 }
 
 /**
@@ -823,12 +830,19 @@ int V4L2VideoDevice::getFormat(V4L2DeviceFormat *format)
  */
 int V4L2VideoDevice::tryFormat(V4L2DeviceFormat *format)
 {
-	if (caps_.isMeta())
-		return trySetFormatMeta(format, false);
-	else if (caps_.isMultiplanar())
-		return trySetFormatMultiplane(format, false);
-	else
+	switch (bufferType_) {
+	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
+	case V4L2_BUF_TYPE_VIDEO_OUTPUT:
 		return trySetFormatSingleplane(format, false);
+	case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
+	case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
+		return trySetFormatMultiplane(format, false);
+	case V4L2_BUF_TYPE_META_CAPTURE:
+	case V4L2_BUF_TYPE_META_OUTPUT:
+		return trySetFormatMeta(format, false);
+	default:
+		return -EINVAL;
+	}
 }
 
 /**
@@ -842,13 +856,25 @@ int V4L2VideoDevice::tryFormat(V4L2DeviceFormat *format)
  */
 int V4L2VideoDevice::setFormat(V4L2DeviceFormat *format)
 {
-	int ret = 0;
-	if (caps_.isMeta())
-		ret = trySetFormatMeta(format, true);
-	else if (caps_.isMultiplanar())
-		ret = trySetFormatMultiplane(format, true);
-	else
+	int ret;
+
+	switch (bufferType_) {
+	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
+	case V4L2_BUF_TYPE_VIDEO_OUTPUT:
 		ret = trySetFormatSingleplane(format, true);
+		break;
+	case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
+	case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
+		ret = trySetFormatMultiplane(format, true);
+		break;
+	case V4L2_BUF_TYPE_META_CAPTURE:
+	case V4L2_BUF_TYPE_META_OUTPUT:
+		ret = trySetFormatMeta(format, true);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
 
 	/* Cache the set format on success. */
 	if (ret)