[libcamera-devel] [PATCH] Revert "libcamera: V4L2Device: Remove the controls order assumption in updateControls()"

[Laurent Pinchart]

This reverts commit 34bee5e84ecba01e0ded5cacbc46c277c5a0edba.

The commit introduced a breakage in the master branch, reported by
linux-surface users already. Let's revert it while discussing the
propert fix.

Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
 src/libcamera/v4l2_device.cpp | 26 +++++++++++++++++++-------
 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp
index 7f7e5b8fdf09..caafbc2d16bb 100644
--- a/src/libcamera/v4l2_device.cpp
+++ b/src/libcamera/v4l2_device.cpp
@@ -244,6 +244,12 @@ ControlList V4L2Device::getControls(const std::vector<uint32_t> &ids)
 
 	ControlList ctrls{ controls_ };
 
+	/*
+	 * Start by filling the ControlList. This can't be combined with filling
+	 * v4l2Ctrls, as updateControls() relies on both containers having the
+	 * same order, and the control list is based on a map, which is not
+	 * sorted by insertion order.
+	 */
 	for (uint32_t id : ids) {
 		const auto iter = controls_.find(id);
 		if (iter == controls_.end()) {
@@ -617,13 +623,19 @@ void V4L2Device::updateControlInfo()
 void V4L2Device::updateControls(ControlList *ctrls,
 				Span<const v4l2_ext_control> v4l2Ctrls)
 {
-	for (const v4l2_ext_control &v4l2Ctrl : v4l2Ctrls) {
-		const unsigned int id = v4l2Ctrl.id;
+	unsigned int i = 0;
+	for (auto &ctrl : *ctrls) {
+		if (i == v4l2Ctrls.size())
+			break;
 
-		ControlValue value = ctrls->get(id);
-		switch (value.type()) {
+		const struct v4l2_ext_control *v4l2Ctrl = &v4l2Ctrls[i];
+		unsigned int id = ctrl.first;
+		ControlValue &value = ctrl.second;
+
+		const auto iter = controls_.find(id);
+		switch (iter->first->type()) {
 		case ControlTypeInteger64:
-			value.set<int64_t>(v4l2Ctrl.value64);
+			value.set<int64_t>(v4l2Ctrl->value64);
 			break;
 
 		case ControlTypeByte:
@@ -638,11 +650,11 @@ void V4L2Device::updateControls(ControlList *ctrls,
 			 * \todo To be changed when support for string controls
 			 * will be added.
 			 */
-			value.set<int32_t>(v4l2Ctrl.value);
+			value.set<int32_t>(v4l2Ctrl->value);
 			break;
 		}
 
-		ctrls->set(id, value);
+		i++;
 	}
 }
 
-- 
Regards,

Laurent Pinchart