[libcamera-devel] [PATCH v3] libcamera: device_enumerator: fix udev media graph loading dependency

Laurent Pinchart laurent.pinchart at ideasonboard.com
Fri Sep 13 00:55:32 CEST 2019


Hi Kieran,

On Tue, Sep 10, 2019 at 10:36:57AM +0100, Kieran Bingham wrote:
> Hi Paul,
> 
> This patch breaks the V4L2 M2M Device operation.
> 
> Could you please test and investigate what happened?

I've posted a patch series that should fix this. Could you and Paul have
a look ?

> You need to load the vim2m kernel module to enable the test.
> 
> Perhaps we should document somewhere that to run the test you must load
> all of:
>   vivid, vimc, vim2m
> 
> 
> libcamera$ ./lcdebug ./build/test/v4l2_videodevice/v4l2_m2mdevice
> [10:26:49.846673285]  DBG Pipeline pipeline_handler.cpp:578 Registered
> pipeline handler "PipelineHandlerUVC"
> [10:26:49.846917535]  DBG Pipeline pipeline_handler.cpp:578 Registered
> pipeline handler "PipelineHandlerVimc"
> [10:26:49.847014380]  DBG Pipeline pipeline_handler.cpp:578 Registered
> pipeline handler "PipelineHandlerIPU3"
> [10:26:49.847083634]  DBG Pipeline pipeline_handler.cpp:578 Registered
> pipeline handler "PipelineHandlerRkISP1"
> [10:26:49.847211601]  DBG IPAProxy ipa_proxy.cpp:177 Registered proxy
> "IPAProxyLinux"
> [10:26:49.852556351]  DBG DeviceEnumerator device_enumerator.cpp:224 New
> media device "uvcvideo" created from /dev/media0
> [10:26:49.853640081]  DBG DeviceEnumerator device_enumerator.cpp:242
> Added device /dev/media0: uvcvideo
> [10:26:49.853945949]  DBG DeviceEnumerator device_enumerator.cpp:224 New
> media device "uvcvideo" created from /dev/media1
> [10:26:49.854690732]  DBG DeviceEnumerator device_enumerator.cpp:242
> Added device /dev/media1: uvcvideo
> [10:26:49.854961313]  DBG DeviceEnumerator device_enumerator.cpp:224 New
> media device "vim2m" created from /dev/media4
> [10:26:49.855326614]  DBG DeviceEnumerator device_enumerator.cpp:242
> Added device /dev/media4: vim2m
> [10:26:49.855602157]  DBG DeviceEnumerator device_enumerator.cpp:224 New
> media device "vimc" created from /dev/media2
> [10:26:49.858106935]  DBG DeviceEnumerator device_enumerator.cpp:242
> Added device /dev/media2: vimc
> [10:26:49.858379665]  DBG DeviceEnumerator device_enumerator.cpp:224 New
> media device "vivid" created from /dev/media3
> [10:26:49.860014947]  DBG DeviceEnumerator device_enumerator.cpp:242
> Added device /dev/media3: vivid
> [10:26:49.860995086]  DBG DeviceEnumerator device_enumerator.cpp:299
> Successful match for media device "vim2m"
> [10:26:49.861182547]  ERR V4L2 v4l2_videodevice.cpp:1305 Failed to open
> V4L2 M2M device: No such file or directory
> Failed to open VIM2M device
> 
> 
> (The deviceNodes for the V4L2 M2M device entities are "")
> 
> 
> libcamera$ git revert 6e620349009de675250a7e3e753480b85a6df10b
> 
> libcamera$ ./lcdebug ./build/test/v4l2_videodevice/v4l2_m2mdevice
> [10:27:56.365739511]  DBG Pipeline pipeline_handler.cpp:578 Registered
> pipeline handler "PipelineHandlerUVC"
> [10:27:56.366391361]  DBG Pipeline pipeline_handler.cpp:578 Registered
> pipeline handler "PipelineHandlerVimc"
> [10:27:56.366530058]  DBG Pipeline pipeline_handler.cpp:578 Registered
> pipeline handler "PipelineHandlerIPU3"
> [10:27:56.366606163]  DBG Pipeline pipeline_handler.cpp:578 Registered
> pipeline handler "PipelineHandlerRkISP1"
> [10:27:56.366875927]  DBG IPAProxy ipa_proxy.cpp:177 Registered proxy
> "IPAProxyLinux"
> [10:27:56.371587913]  DBG DeviceEnumerator device_enumerator.cpp:219 New
> media device "uvcvideo" created from /dev/media0
> [10:27:56.372700681]  DBG DeviceEnumerator device_enumerator.cpp:238
> Added device /dev/media0: uvcvideo
> [10:27:56.373059113]  DBG DeviceEnumerator device_enumerator.cpp:219 New
> media device "uvcvideo" created from /dev/media1
> [10:27:56.373295221]  DBG DeviceEnumerator device_enumerator.cpp:238
> Added device /dev/media1: uvcvideo
> [10:27:56.373483256]  DBG DeviceEnumerator device_enumerator.cpp:219 New
> media device "vim2m" created from /dev/media4
> [10:27:56.373688268]  DBG DeviceEnumerator device_enumerator.cpp:238
> Added device /dev/media4: vim2m
> [10:27:56.373946704]  DBG DeviceEnumerator device_enumerator.cpp:219 New
> media device "vimc" created from /dev/media2
> [10:27:56.374664475]  DBG DeviceEnumerator device_enumerator.cpp:238
> Added device /dev/media2: vimc
> [10:27:56.374821368]  DBG DeviceEnumerator device_enumerator.cpp:219 New
> media device "vivid" created from /dev/media3
> [10:27:56.375225906]  DBG DeviceEnumerator device_enumerator.cpp:238
> Added device /dev/media3: vivid
> [10:27:56.375801230]  DBG DeviceEnumerator device_enumerator.cpp:297
> Successful match for media device "vim2m"
> [10:27:56.376029192]  DBG V4L2 v4l2_videodevice.cpp:444
> /dev/video9[out]: Opened device platform:vim2m: vim2m: vim2m
> [10:27:56.376150346]  DBG V4L2 v4l2_videodevice.cpp:444
> /dev/video9[cap]: Opened device platform:vim2m: vim2m: vim2m
> [10:27:56.376491815]  DBG V4L2 v4l2_videodevice.cpp:824
> /dev/video9[cap]: 4 buffers requested.
> [10:27:56.376549753]  DBG V4L2 v4l2_videodevice.cpp:909
> /dev/video9[cap]: Buffer 0 plane 0: length=614400
> [10:27:56.376672692]  DBG V4L2 v4l2_videodevice.cpp:909
> /dev/video9[cap]: Buffer 1 plane 0: length=614400
> [10:27:56.376717010]  DBG V4L2 v4l2_videodevice.cpp:909
> /dev/video9[cap]: Buffer 2 plane 0: length=614400
> [10:27:56.376775343]  DBG V4L2 v4l2_videodevice.cpp:909
> /dev/video9[cap]: Buffer 3 plane 0: length=614400
> [10:27:56.377028570]  DBG V4L2 v4l2_videodevice.cpp:824
> /dev/video9[out]: 4 buffers requested.
> [10:27:56.377072622]  DBG V4L2 v4l2_videodevice.cpp:909
> /dev/video9[out]: Buffer 0 plane 0: length=614400
> [10:27:56.377125986]  DBG V4L2 v4l2_videodevice.cpp:909
> /dev/video9[out]: Buffer 1 plane 0: length=614400
> [10:27:56.377150123]  DBG V4L2 v4l2_videodevice.cpp:909
> /dev/video9[out]: Buffer 2 plane 0: length=614400
> [10:27:56.377167310]  DBG V4L2 v4l2_videodevice.cpp:909
> /dev/video9[out]: Buffer 3 plane 0: length=614400
> [10:27:56.377212874]  DBG V4L2 v4l2_videodevice.cpp:1023
> /dev/video9[cap]: Queueing buffer 0
> [10:27:56.377301766]  DBG V4L2 v4l2_videodevice.cpp:1023
> /dev/video9[cap]: Queueing buffer 1
> [10:27:56.377331186]  DBG V4L2 v4l2_videodevice.cpp:1023
> /dev/video9[cap]: Queueing buffer 2
> 
> ... Test continues ...
> 
> --
> Regards
> 
> Kieran
> 
> 
> 
> On 09/09/2019 00:11, Laurent Pinchart wrote:
> > Hi Paul,
> > 
> > Thank you for the patch.
> > 
> > On Sun, Sep 08, 2019 at 01:00:06AM -0400, Paul Elder wrote:
> >> When a MediaDevice is enumerated and populated by the
> >> DeviceEnumeratorUdev, there is a possibility that the member device
> >> nodes of the media graph would not be ready (either not created, or
> >> without proper permissions set by udev yet). The MediaDevice is still
> >> passed up to the pipeline handler, where an attempt to access the device
> >> nodes will fail in EPERM. This whole issue is especially likely to
> >> happen when libcamera is run at system init time.
> >>
> >> To fix this, we first split DeviceEnumerator::addDevice() into three
> >> methods:
> >> - createDevice() to simply create the MediaDevice
> >> - populateMediaDevice() to populate the MediaDevice
> >> - addDevice() to pass the MediaDevice up to the pipeline handler
> >>
> >> DeviceEnumeratorSysfs calls these methods in succession, similar to what
> >> it did before when they were all together as addDevice().
> >>
> >> DeviceEnumeratorUdev additionally keeps a map of MediaDevices to a list
> >> of pending device nodes (plus some other auxillary maps), and a simple
> >> list of orphan device nodes. If a v4l device node is ready and there
> >> does not exist any MediaDevice node for it, then it goes to the orphan
> >> list, otherwise it is initialized and removed from the pending list of
> >> the corresponding MediaDevice in the dependency map. When a MediaDevice
> >> is populated via DeviceEnumeratorUdev::populateMediaDevice(), it first
> >> checks the orphan list to see if the device nodes it needs are there,
> >> otherwise it tries to initialize the device nodes and if it fails, then
> >> it adds the device nodes it wants to its list in the dependency map.
> >>
> >> This allows MediaDevice instances to be created and initialized properly
> >> with udev when v4l device nodes in the media graph may not be ready when
> >> the MediaDevice is populated.
> >>
> >> Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
> > 
> > Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > 
> >> ---
> >> Changes in v3:
> >> - remove adding any V4L2 nodes that are already ready, to prevent any
> >>   potential racing
> >> - other minor changes
> >> - we're keeing the name populateMediaDevice()
> >>
> >> Changes in v2:
> >> - add documentation
> >> - better name for the maps
> >> - other minor changes
> >>
> >> ---
> >>  src/libcamera/device_enumerator.cpp           |  54 +++----
> >>  src/libcamera/device_enumerator_sysfs.cpp     |  35 ++++-
> >>  src/libcamera/device_enumerator_udev.cpp      | 135 +++++++++++++++++-
> >>  src/libcamera/include/device_enumerator.h     |   3 +-
> >>  .../include/device_enumerator_sysfs.h         |   6 +-
> >>  .../include/device_enumerator_udev.h          |  16 +++
> >>  6 files changed, 216 insertions(+), 33 deletions(-)
> >>
> >> diff --git a/src/libcamera/device_enumerator.cpp b/src/libcamera/device_enumerator.cpp
> >> index 60c918f..e76438a 100644
> >> --- a/src/libcamera/device_enumerator.cpp
> >> +++ b/src/libcamera/device_enumerator.cpp
> >> @@ -195,16 +195,21 @@ DeviceEnumerator::~DeviceEnumerator()
> >>   */
> >>  
> >>  /**
> >> - * \brief Add a media device to the enumerator
> >> - * \param[in] deviceNode path to the media device to add
> >> + * \brief Create a media device instance
> >> + * \param[in] deviceNode path to the media device to create
> >>   *
> >> - * Create a media device for the \a deviceNode, open it, populate its media graph,
> >> - * and look up device nodes associated with all entities. Store the media device
> >> - * in the internal list for later matching with pipeline handlers.
> >> + * Create a media device for the \a deviceNode, open it, and populate its
> >> + * media graph. The device enumerator shall then populate the media device by
> >> + * associating device nodes with entities using MediaEntity::setDeviceNode().
> >> + * This process is specific to each device enumerator, and the device enumerator
> >> + * shall ensure that device nodes are ready to be used (for instance, if
> >> + * applicable, by waiting for device nodes to be created and access permissions
> >> + * to be set by the system). Once done, it shall add the media device to the
> >> + * system with addDevice().
> >>   *
> >> - * \return 0 on success or a negative error code otherwise
> >> + * \return Created media device instance on success, or nullptr otherwise
> >>   */
> >> -int DeviceEnumerator::addDevice(const std::string &deviceNode)
> >> +std::shared_ptr<MediaDevice> DeviceEnumerator::createDevice(const std::string &deviceNode)
> >>  {
> >>  	std::shared_ptr<MediaDevice> media = std::make_shared<MediaDevice>(deviceNode);
> >>  
> >> @@ -213,34 +218,31 @@ int DeviceEnumerator::addDevice(const std::string &deviceNode)
> >>  		LOG(DeviceEnumerator, Info)
> >>  			<< "Unable to populate media device " << deviceNode
> >>  			<< " (" << strerror(-ret) << "), skipping";
> >> -		return ret;
> >> +		return nullptr;
> >>  	}
> >>  
> >>  	LOG(DeviceEnumerator, Debug)
> >>  		<< "New media device \"" << media->driver()
> >>  		<< "\" created from " << deviceNode;
> >>  
> >> -	/* Associate entities to device node paths. */
> >> -	for (MediaEntity *entity : media->entities()) {
> >> -		if (entity->deviceMajor() == 0 && entity->deviceMinor() == 0)
> >> -			continue;
> >> -
> >> -		std::string deviceNode = lookupDeviceNode(entity->deviceMajor(),
> >> -							  entity->deviceMinor());
> >> -		if (deviceNode.empty())
> >> -			return -EINVAL;
> >> -
> >> -		ret = entity->setDeviceNode(deviceNode);
> >> -		if (ret)
> >> -			return ret;
> >> -	}
> >> +	return media;
> >> +}
> >>  
> >> +/**
> >> + * \brief Add a media device to the enumerator
> >> + * \param[in] media media device instance to add
> >> + *
> >> + * Store the media device in the internal list for later matching with
> >> + * pipeline handlers. \a media shall be created with createDevice() first.
> >> + * This method shall be called after all members of the entities of the
> >> + * media graph have been confirmed to be initialized.
> >> + */
> >> +void DeviceEnumerator::addDevice(const std::shared_ptr<MediaDevice> &media)
> >> +{
> >>  	LOG(DeviceEnumerator, Debug)
> >> -		<< "Added device " << deviceNode << ": " << media->driver();
> >> -
> >> -	devices_.push_back(std::move(media));
> >> +		<< "Added device " << media->deviceNode() << ": " << media->driver();
> >>  
> >> -	return 0;
> >> +	devices_.push_back(media);
> >>  }
> >>  
> >>  /**
> >> diff --git a/src/libcamera/device_enumerator_sysfs.cpp b/src/libcamera/device_enumerator_sysfs.cpp
> >> index f3054d5..78a7da8 100644
> >> --- a/src/libcamera/device_enumerator_sysfs.cpp
> >> +++ b/src/libcamera/device_enumerator_sysfs.cpp
> >> @@ -18,6 +18,7 @@
> >>  #include <unistd.h>
> >>  
> >>  #include "log.h"
> >> +#include "media_device.h"
> >>  
> >>  namespace libcamera {
> >>  
> >> @@ -32,6 +33,7 @@ int DeviceEnumeratorSysfs::enumerate()
> >>  {
> >>  	struct dirent *ent;
> >>  	DIR *dir;
> >> +	int ret = 0;
> >>  
> >>  	static const char * const sysfs_dirs[] = {
> >>  		"/sys/subsystem/media/devices",
> >> @@ -71,11 +73,42 @@ int DeviceEnumeratorSysfs::enumerate()
> >>  			continue;
> >>  		}
> >>  
> >> -		addDevice(devnode);
> >> +		std::shared_ptr<MediaDevice> media = createDevice(devnode);
> >> +		if (!media) {
> >> +			ret = -ENODEV;
> >> +			break;
> >> +		}
> >> +
> >> +		if (populateMediaDevice(media) < 0) {
> >> +			ret = -ENODEV;
> >> +			break;
> >> +		}
> >> +
> >> +		addDevice(media);
> >>  	}
> >>  
> >>  	closedir(dir);
> >>  
> >> +	return ret;
> >> +}
> >> +
> >> +int DeviceEnumeratorSysfs::populateMediaDevice(const std::shared_ptr<MediaDevice> &media)
> >> +{
> >> +	/* Associate entities to device node paths. */
> >> +	for (MediaEntity *entity : media->entities()) {
> >> +		if (entity->deviceMajor() == 0 && entity->deviceMinor() == 0)
> >> +			continue;
> >> +
> >> +		std::string deviceNode = lookupDeviceNode(entity->deviceMajor(),
> >> +							  entity->deviceMinor());
> >> +		if (deviceNode.empty())
> >> +			return -EINVAL;
> >> +
> >> +		int ret = entity->setDeviceNode(deviceNode);
> >> +		if (ret)
> >> +			return ret;
> >> +	}
> >> +
> >>  	return 0;
> >>  }
> >>  
> >> diff --git a/src/libcamera/device_enumerator_udev.cpp b/src/libcamera/device_enumerator_udev.cpp
> >> index 86f6ca1..40853e7 100644
> >> --- a/src/libcamera/device_enumerator_udev.cpp
> >> +++ b/src/libcamera/device_enumerator_udev.cpp
> >> @@ -7,6 +7,10 @@
> >>  
> >>  #include "device_enumerator_udev.h"
> >>  
> >> +#include <algorithm>
> >> +#include <list>
> >> +#include <map>
> >> +
> >>  #include <fcntl.h>
> >>  #include <libudev.h>
> >>  #include <string.h>
> >> @@ -17,6 +21,7 @@
> >>  #include <libcamera/event_notifier.h>
> >>  
> >>  #include "log.h"
> >> +#include "media_device.h"
> >>  
> >>  namespace libcamera {
> >>  
> >> @@ -57,9 +62,40 @@ int DeviceEnumeratorUdev::init()
> >>  	if (ret < 0)
> >>  		return ret;
> >>  
> >> +	ret = udev_monitor_filter_add_match_subsystem_devtype(monitor_, "video4linux",
> >> +							      nullptr);
> >> +	if (ret < 0)
> >> +		return ret;
> >> +
> >>  	return 0;
> >>  }
> >>  
> >> +int DeviceEnumeratorUdev::addUdevDevice(struct udev_device *dev)
> >> +{
> >> +	const char *subsystem = udev_device_get_subsystem(dev);
> >> +	if (!subsystem)
> >> +		return -ENODEV;
> >> +
> >> +	if (!strcmp(subsystem, "media")) {
> >> +		std::shared_ptr<MediaDevice> media =
> >> +			createDevice(udev_device_get_devnode(dev));
> >> +		if (!media)
> >> +			return -ENODEV;
> >> +
> >> +		int ret = populateMediaDevice(media);
> >> +		if (ret == 0)
> >> +			addDevice(media);
> >> +		return 0;
> >> +	}
> >> +
> >> +	if (!strcmp(subsystem, "video4linux")) {
> >> +		addV4L2Device(udev_device_get_devnum(dev));
> >> +		return 0;
> >> +	}
> >> +
> >> +	return -ENODEV;
> >> +}
> >> +
> >>  int DeviceEnumeratorUdev::enumerate()
> >>  {
> >>  	struct udev_enumerate *udev_enum = nullptr;
> >> @@ -74,6 +110,14 @@ int DeviceEnumeratorUdev::enumerate()
> >>  	if (ret < 0)
> >>  		goto done;
> >>  
> >> +	ret = udev_enumerate_add_match_subsystem(udev_enum, "video4linux");
> >> +	if (ret < 0)
> >> +		goto done;
> >> +
> >> +	ret = udev_enumerate_add_match_is_initialized(udev_enum);
> >> +	if (ret < 0)
> >> +		goto done;
> >> +
> >>  	ret = udev_enumerate_scan_devices(udev_enum);
> >>  	if (ret < 0)
> >>  		goto done;
> >> @@ -102,10 +146,12 @@ int DeviceEnumeratorUdev::enumerate()
> >>  			goto done;
> >>  		}
> >>  
> >> -		addDevice(devnode);
> >> -
> >> +		ret = addUdevDevice(dev);
> >>  		udev_device_unref(dev);
> >> +		if (ret < 0)
> >> +			break;
> >>  	}
> >> +
> >>  done:
> >>  	udev_enumerate_unref(udev_enum);
> >>  	if (ret < 0)
> >> @@ -122,6 +168,43 @@ done:
> >>  	return 0;
> >>  }
> >>  
> >> +int DeviceEnumeratorUdev::populateMediaDevice(const std::shared_ptr<MediaDevice> &media)
> >> +{
> >> +	unsigned int pendingNodes = 0;
> >> +	int ret;
> >> +
> >> +	/* Associate entities to device node paths. */
> >> +	for (MediaEntity *entity : media->entities()) {
> >> +		if (entity->deviceMajor() == 0 && entity->deviceMinor() == 0)
> >> +			continue;
> >> +
> >> +		std::string deviceNode = lookupDeviceNode(entity->deviceMajor(),
> >> +							  entity->deviceMinor());
> >> +		dev_t devnum = makedev(entity->deviceMajor(),
> >> +				       entity->deviceMinor());
> >> +
> >> +		/* Take device from orphan list first, if it is in the list. */
> >> +		if (std::find(orphans_.begin(), orphans_.end(), devnum) != orphans_.end()) {
> >> +			if (deviceNode.empty())
> >> +				return -EINVAL;
> >> +
> >> +			ret = entity->setDeviceNode(deviceNode);
> >> +			if (ret)
> >> +				return ret;
> >> +
> >> +			orphans_.remove(devnum);
> >> +			continue;
> >> +		}
> >> +
> >> +		deps_[media].push_back(devnum);
> >> +		devnumToDevice_[devnum] = media;
> >> +		devnumToEntity_[devnum] = entity;
> >> +		pendingNodes++;
> >> +	}
> >> +
> >> +	return pendingNodes;
> >> +}
> >> +
> >>  std::string DeviceEnumeratorUdev::lookupDeviceNode(int major, int minor)
> >>  {
> >>  	struct udev_device *device;
> >> @@ -143,6 +226,48 @@ std::string DeviceEnumeratorUdev::lookupDeviceNode(int major, int minor)
> >>  	return deviceNode;
> >>  }
> >>  
> >> +/**
> >> + * \brief Add a V4L2 device to the media device that it belongs to
> >> + * \param[in] devnum major:minor number of V4L2 device to add, as a dev_t
> >> + *
> >> + * Add V4L2 device identified by \a devnum to the MediaDevice that it belongs
> >> + * to, if such a MediaDevice has been created. Otherwise add the V4L2 device
> >> + * to the orphan list. If the V4L2 device is added to a MediaDevice, and it is
> >> + * the last V4L2 device that the MediaDevice needs, then the MediaDevice is
> >> + * added to the DeviceEnumerator, where it is available for pipeline handlers.
> >> + *
> >> + * \return 0 on success or a negative error code otherwise
> >> + */
> >> +int DeviceEnumeratorUdev::addV4L2Device(dev_t devnum)
> >> +{
> >> +	MediaEntity *entity = devnumToEntity_[devnum];
> >> +	if (!entity) {
> >> +		orphans_.push_back(devnum);
> >> +		return 0;
> >> +	}
> >> +
> >> +	std::string deviceNode = lookupDeviceNode(entity->deviceMajor(),
> >> +						  entity->deviceMinor());
> >> +	if (deviceNode.empty())
> >> +		return -EINVAL;
> >> +
> >> +	int ret = entity->setDeviceNode(deviceNode);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	std::shared_ptr<MediaDevice> media = devnumToDevice_[devnum];
> >> +	deps_[media].remove(devnum);
> >> +	devnumToDevice_.erase(devnum);
> >> +	devnumToEntity_.erase(devnum);
> >> +
> >> +	if (deps_[media].empty()) {
> >> +		addDevice(media);
> >> +		deps_.erase(media);
> >> +	}
> >> +
> >> +	return 0;
> >> +}
> >> +
> >>  void DeviceEnumeratorUdev::udevNotify(EventNotifier *notifier)
> >>  {
> >>  	struct udev_device *dev = udev_monitor_receive_device(monitor_);
> >> @@ -153,9 +278,11 @@ void DeviceEnumeratorUdev::udevNotify(EventNotifier *notifier)
> >>  		<< action << " device " << udev_device_get_devnode(dev);
> >>  
> >>  	if (action == "add") {
> >> -		addDevice(deviceNode);
> >> +		addUdevDevice(dev);
> >>  	} else if (action == "remove") {
> >> -		removeDevice(deviceNode);
> >> +		const char *subsystem = udev_device_get_subsystem(dev);
> >> +		if (subsystem && !strcmp(subsystem, "media"))
> >> +			removeDevice(deviceNode);
> >>  	}
> >>  
> >>  	udev_device_unref(dev);
> >> diff --git a/src/libcamera/include/device_enumerator.h b/src/libcamera/include/device_enumerator.h
> >> index 02aec3b..c5d26f1 100644
> >> --- a/src/libcamera/include/device_enumerator.h
> >> +++ b/src/libcamera/include/device_enumerator.h
> >> @@ -44,7 +44,8 @@ public:
> >>  	std::shared_ptr<MediaDevice> search(const DeviceMatch &dm);
> >>  
> >>  protected:
> >> -	int addDevice(const std::string &deviceNode);
> >> +	std::shared_ptr<MediaDevice> createDevice(const std::string &deviceNode);
> >> +	void addDevice(const std::shared_ptr<MediaDevice> &media);
> >>  	void removeDevice(const std::string &deviceNode);
> >>  
> >>  private:
> >> diff --git a/src/libcamera/include/device_enumerator_sysfs.h b/src/libcamera/include/device_enumerator_sysfs.h
> >> index 8d3adc9..242b22b 100644
> >> --- a/src/libcamera/include/device_enumerator_sysfs.h
> >> +++ b/src/libcamera/include/device_enumerator_sysfs.h
> >> @@ -7,10 +7,13 @@
> >>  #ifndef __LIBCAMERA_DEVICE_ENUMERATOR_SYSFS_H__
> >>  #define __LIBCAMERA_DEVICE_ENUMERATOR_SYSFS_H__
> >>  
> >> +#include <memory>
> >>  #include <string>
> >>  
> >>  #include "device_enumerator.h"
> >>  
> >> +class MediaDevice;
> >> +
> >>  namespace libcamera {
> >>  
> >>  class DeviceEnumeratorSysfs final : public DeviceEnumerator
> >> @@ -20,7 +23,8 @@ public:
> >>  	int enumerate();
> >>  
> >>  private:
> >> -	std::string lookupDeviceNode(int major, int minor);
> >> +	int populateMediaDevice(const std::shared_ptr<MediaDevice> &media);
> >> +	std::string lookupDeviceNode(int major, int minor) final;
> >>  };
> >>  
> >>  } /* namespace libcamera */
> >> diff --git a/src/libcamera/include/device_enumerator_udev.h b/src/libcamera/include/device_enumerator_udev.h
> >> index 80f9372..5bdcdea 100644
> >> --- a/src/libcamera/include/device_enumerator_udev.h
> >> +++ b/src/libcamera/include/device_enumerator_udev.h
> >> @@ -7,16 +7,23 @@
> >>  #ifndef __LIBCAMERA_DEVICE_ENUMERATOR_UDEV_H__
> >>  #define __LIBCAMERA_DEVICE_ENUMERATOR_UDEV_H__
> >>  
> >> +#include <list>
> >> +#include <map>
> >> +#include <memory>
> >>  #include <string>
> >> +#include <sys/types.h>
> >>  
> >>  #include "device_enumerator.h"
> >>  
> >>  struct udev;
> >> +struct udev_device;
> >>  struct udev_monitor;
> >>  
> >>  namespace libcamera {
> >>  
> >>  class EventNotifier;
> >> +class MediaDevice;
> >> +class MediaEntity;
> >>  
> >>  class DeviceEnumeratorUdev : public DeviceEnumerator
> >>  {
> >> @@ -32,8 +39,17 @@ private:
> >>  	struct udev_monitor *monitor_;
> >>  	EventNotifier *notifier_;
> >>  
> >> +	std::map<std::shared_ptr<MediaDevice>, std::list<dev_t>> deps_;
> >> +	std::map<dev_t, std::shared_ptr<MediaDevice>> devnumToDevice_;
> >> +	std::map<dev_t, MediaEntity *> devnumToEntity_;
> >> +
> >> +	std::list<dev_t> orphans_;
> >> +
> >> +	int addUdevDevice(struct udev_device *dev);
> >> +	int populateMediaDevice(const std::shared_ptr<MediaDevice> &media);
> >>  	std::string lookupDeviceNode(int major, int minor) final;
> >>  
> >> +	int addV4L2Device(dev_t devnum);
> >>  	void udevNotify(EventNotifier *notifier);
> >>  };
> >>  

-- 
Regards,

Laurent Pinchart


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