On 03/24/2015 12:49 AM, Divneil Rai WADHAWAN wrote: > Hello, > > I have a use case, where, I am using subdev configuration to setup video capture. > The pipeline is something like this: > > Subdevs: sd_display, sd_capture > Vdev: vcapture > > (0)sd_display(1) -> (0)sd_capture(1)->(0)vcapture > > sd_display informs sd_capture of video resolution change and vdev using sd_capture needs to be informed, so, that vdev capture can be stopped. > > Here, subdev notification/subscription is missing to/from vdev, in my understanding. > subdev can send notification to v4l2-dev, but not vdev. > Can you help with that? Thanks. This is correct. The subdev doesn't and cannot know anything about which video node(s) need(s) to send out a source change event. The only driver that can is the top-level driver that knows the topology and can map the event from the sd to the correct video_device. If your driver uses the media controller, then it should be possible to write a generic function that would use the topology to discover automatically which video_device nodes are linked to the sd and propagate the event to those video devices. Such a generic v4l2_dev notify function doesn't exist today though. Patches are welcome. If the driver doesn't use the media controller, then the top-level driver should provide this knowledge in its v4l2_dev notifier function. Regards, Hans -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
