[PATCH] libcamera: fix maybe-uninitialized error

[Jacopo Mondi]

Hi Stefan

On Thu, Jun 27, 2024 at 03:31:00PM GMT, Stefan Klug wrote:
> The gcc used in my current buildroot (Version 12.3) errors out with
> -Wmaybe-uninitialized. Fix that.
>
> Signed-off-by: Stefan Klug <stefan.klug at ideasonboard.com>
> ---
>
> @Naush: Could you have a look at the rpi specific changes? Specifically
> I'm not sure if the change in AwbConfig::read() is correct. It was
> unclear to me if there are cases where line 125 should return 0 even
> though a error got logged one line above.
>
> Regards,
> Stefan
>
>
>  src/ipa/libipa/exposure_mode_helper.cpp   | 15 ++++++---------
>  src/ipa/rpi/controller/rpi/awb.cpp        |  2 +-
>  src/libcamera/device_enumerator_sysfs.cpp |  2 +-
>  src/libcamera/pipeline/rpi/vc4/vc4.cpp    |  2 +-
>  4 files changed, 9 insertions(+), 12 deletions(-)
>
> diff --git a/src/ipa/libipa/exposure_mode_helper.cpp b/src/ipa/libipa/exposure_mode_helper.cpp
> index 683a564a01c8..9d1387636d05 100644
> --- a/src/ipa/libipa/exposure_mode_helper.cpp
> +++ b/src/ipa/libipa/exposure_mode_helper.cpp
> @@ -166,7 +166,7 @@ ExposureModeHelper::splitExposure(utils::Duration exposure) const
>  		return { minShutter_, minGain_, exposure / (minShutter_ * minGain_) };
>
>  	utils::Duration shutter;
> -	double stageGain;
> +	double stageGain = 1.0;
>  	double gain;
>
>  	for (unsigned int stage = 0; stage < gains_.size(); stage++) {
> @@ -198,15 +198,12 @@ ExposureModeHelper::splitExposure(utils::Duration exposure) const
>  	}
>
>  	/*
> -	 * From here on all we can do is max out the shutter time, followed by
> -	 * the analogue gain. If we still haven't achieved the target we send
> -	 * the rest of the exposure time to digital gain. If we were given no
> -	 * stages to use then set stageGain to 1.0 so that shutter time is maxed
> -	 * before gain touched at all.
> +	 * From here on all we can do is max out the shutter time, followed by the
> +	 * analogue gain. If we still haven't achieved the target we send the rest
> +	 * of the exposure time to digital gain. If we were given no stages to use
> +	 * then the default stageGain of 1.0 is used so that shutter time is maxed
> +	 * before gain is touched at all.

No need to go over 80-cols

>  	 */
> -	if (gains_.empty())
> -		stageGain = 1.0;
> -
>  	shutter = clampShutter(exposure / clampGain(stageGain));
>  	gain = clampGain(exposure / shutter);
>
> diff --git a/src/ipa/rpi/controller/rpi/awb.cpp b/src/ipa/rpi/controller/rpi/awb.cpp
> index 003c8fa137f3..3503a5ab9218 100644
> --- a/src/ipa/rpi/controller/rpi/awb.cpp
> +++ b/src/ipa/rpi/controller/rpi/awb.cpp
> @@ -91,7 +91,7 @@ static int readCtCurve(ipa::Pwl &ctR, ipa::Pwl &ctB, const libcamera::YamlObject
>
>  int AwbConfig::read(const libcamera::YamlObject &params)
>  {
> -	int ret;
> +	int ret = 0;
>
>  	bayes = params["bayes"].get<int>(1);
>  	framePeriod = params["frame_period"].get<uint16_t>(10);

There's one code path below were you could return 0 on an error
condition

	if (params.contains("priors")) {
		for (const auto &p : params["priors"].asList()) {
			AwbPrior prior;
			ret = prior.read(p);
			if (ret)
				return ret;
			if (!priors.empty() && prior.lux <= priors.back().lux) {
				LOG(RPiAwb, Error) << "AwbConfig: Prior must be ordered in increasing lux value";
				return -EINVAL;
			}
			priors.push_back(prior);
		}
		if (priors.empty()) {
			LOG(RPiAwb, Error) << "AwbConfig: no AWB priors configured";
			return ret; <---- HERE
		}

While at it, could you return -EINVAL here ?

> diff --git a/src/libcamera/device_enumerator_sysfs.cpp b/src/libcamera/device_enumerator_sysfs.cpp
> index fc33ba52b813..7866885c0f73 100644
> --- a/src/libcamera/device_enumerator_sysfs.cpp
> +++ b/src/libcamera/device_enumerator_sysfs.cpp
> @@ -33,7 +33,7 @@ int DeviceEnumeratorSysfs::init()
>  int DeviceEnumeratorSysfs::enumerate()
>  {
>  	struct dirent *ent;
> -	DIR *dir;
> +	DIR *dir = nullptr;
>
>  	static const char * const sysfs_dirs[] = {
>  		"/sys/subsystem/media/devices",
> diff --git a/src/libcamera/pipeline/rpi/vc4/vc4.cpp b/src/libcamera/pipeline/rpi/vc4/vc4.cpp
> index 4a89e35f5d7b..e5b6ef2b37cd 100644
> --- a/src/libcamera/pipeline/rpi/vc4/vc4.cpp
> +++ b/src/libcamera/pipeline/rpi/vc4/vc4.cpp
> @@ -802,7 +802,7 @@ void Vc4CameraData::ispInputDequeue(FrameBuffer *buffer)
>  void Vc4CameraData::ispOutputDequeue(FrameBuffer *buffer)
>  {
>  	RPi::Stream *stream = nullptr;
> -	unsigned int index;
> +	unsigned int index = 0;
>
>  	if (!isRunning())
>  		return;

These two look good!

Thanks
  j

> --
> 2.43.0
>