Thanks Hans for the pointers! Unfortunately, my driver is implemented M2M way. Thanks Vinay > Hi Vinay! > > On 03/12/14 18:58, vkalia@xxxxxxxxxxxxxx wrote: >> Hi >> >> I have a v4l2 driver for a hardware which is capable of taking one input >> and producing two outputs. Eg: Downscaler which takes one input @ 1080p >> and two outputs - one @ 720p and other at VGA. My driver is currently >> implemented as having two capabilities - >> >> 1. V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE >> 2. V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE >> >> Do you know if I can have two CAPTURE capabilities. In that case how do >> I >> distinguish between QBUF/DQBUF of each capability? > > The answer depends on how your driver is organized: is it a > memory-to-memory > device (i.e. it has one video node that is used for both output and > capture > to/from the m2m hardware) or does it have two video nodes, one for output > to > the hardware, one for capture from the hardware? > > In the first case you won't be able to implement this using the M2M API. > > In the second case it is quite easy: you just create another video capture > node. For every frame send to the hardware you'll get a frame back at each > of the two capture nodes, one 720p, one VGA. > > This is actually quite common, there are many drivers that have multiple > video nodes that give back the same video source but in different formats > (e.g. raw video and compressed video). > > Each video node basically represents a DMA engine. So if you have multiple > DMA engines, you'll need multiple video nodes. > > 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
