[libcamera-devel] [PATCH v3 8/8] cam: Add support for viewfinder through DRM/KMS

[Umang Jain]

Hi Laurent,

Thank you for the patch.

On 8/4/21 6:13 PM, Laurent Pinchart wrote:
> Use the KMSSink class to display the viewfinder stream, if any, through
> DRM/KMS. The output connector is selected through the new -D/--display
> argument.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> Reviewed-by: Paul Elder <paul.elder at ideasonboard.com>
Reviewed-by: Umang Jain <umang.jain at ideasonboard.com>
> ---
> Changes since v2:
>
> - Add compile guard around option check
>
> Changes since v1:
>
> - Validate display option in CamApp::init()
> ---
>   src/cam/camera_session.cpp | 30 ++++++++++++++++++++++++++++++
>   src/cam/main.cpp           |  6 ++++++
>   src/cam/main.h             |  1 +
>   3 files changed, 37 insertions(+)
>
> diff --git a/src/cam/camera_session.cpp b/src/cam/camera_session.cpp
> index f34a6ed55ad7..60d640f2b15c 100644
> --- a/src/cam/camera_session.cpp
> +++ b/src/cam/camera_session.cpp
> @@ -16,6 +16,9 @@
>   #include "camera_session.h"
>   #include "event_loop.h"
>   #include "file_sink.h"
> +#ifdef HAVE_KMS
> +#include "kms_sink.h"
> +#endif
>   #include "main.h"
>   #include "stream_options.h"
>   
> @@ -66,6 +69,28 @@ CameraSession::CameraSession(CameraManager *cm,
>   
>   	bool strictFormats = options_.isSet(OptStrictFormats);
>   
> +#ifdef HAVE_KMS
> +	if (options_.isSet(OptDisplay)) {
> +		if (options_.isSet(OptFile)) {
> +			std::cerr << "--display and --file options are mutually exclusive"
> +				  << std::endl;
> +			return;
> +		}
> +
> +		if (roles.size() != 1) {
> +			std::cerr << "Display doesn't support multiple streams"
> +				  << std::endl;
> +			return;
> +		}
> +
> +		if (roles[0] != StreamRole::Viewfinder) {
> +			std::cerr << "Display requires a viewfinder stream"
> +				  << std::endl;
> +			return;
> +		}
> +	}
> +#endif
> +
>   	switch (config->validate()) {
>   	case CameraConfiguration::Valid:
>   		break;
> @@ -161,6 +186,11 @@ int CameraSession::start()
>   
>   	camera_->requestCompleted.connect(this, &CameraSession::requestComplete);
>   
> +#ifdef HAVE_KMS
> +	if (options_.isSet(OptDisplay))
> +		sink_ = std::make_unique<KMSSink>(options_[OptDisplay].toString());
> +#endif
> +
>   	if (options_.isSet(OptFile)) {
>   		if (!options_[OptFile].toString().empty())
>   			sink_ = std::make_unique<FileSink>(options_[OptFile]);
> diff --git a/src/cam/main.cpp b/src/cam/main.cpp
> index 34cbc3229563..c7f664b903e0 100644
> --- a/src/cam/main.cpp
> +++ b/src/cam/main.cpp
> @@ -132,6 +132,12 @@ int CamApp::parseOptions(int argc, char *argv[])
>   			 "Capture until interrupted by user or until <count> frames captured",
>   			 "capture", ArgumentOptional, "count", false,
>   			 OptCamera);
> +#ifdef HAVE_KMS
> +	parser.addOption(OptDisplay, OptionString,
> +			 "Display viewfinder through DRM/KMS on specified connector",
> +			 "display", ArgumentOptional, "connector", false,
> +			 OptCamera);
> +#endif
>   	parser.addOption(OptFile, OptionString,
>   			 "Write captured frames to disk\n"
>   			 "If the file name ends with a '/', it sets the directory in which\n"
> diff --git a/src/cam/main.h b/src/cam/main.h
> index d22451f59817..1c2fab763698 100644
> --- a/src/cam/main.h
> +++ b/src/cam/main.h
> @@ -10,6 +10,7 @@
>   enum {
>   	OptCamera = 'c',
>   	OptCapture = 'C',
> +	OptDisplay = 'D',
>   	OptFile = 'F',
>   	OptHelp = 'h',
>   	OptInfo = 'I',