Hi Vincent, On Mon, Jan 09, 2017 at 03:49:00PM +0000, Vincent ABRIOU wrote: > > > On 01/09/2017 04:37 PM, Laurent Pinchart wrote: > > Hi Vincent, > > > > Thank you for the patch. > > > > On Monday 03 Oct 2016 13:27:16 Vincent Abriou wrote: > >> Allow uvcvideo compatible devices to allocate their output buffers using > >> contiguous DMA buffers. > > > > Why do you need this ? If it's for buffer sharing with a device that requires > > dma-contig, can't you allocate the buffers on the other device and import them > > on the UVC side ? > > > > Hi Laurent, > > I need this using Gstreamer simple pipeline to connect an usb webcam > (v4l2src) with a display (waylandsink) activating the zero copy path. > > The waylandsink plugin does not have any contiguous memory pool to > allocate contiguous buffer. So it is up to the upstream element, here > v4l2src, to provide such contiguous buffers. Do you need (physically) contiguous memory? The DMA-BUF API does help sharing the buffers but it, at least currently, does not help allocating memory or specifying a common format so that all the devices the buffer needs to be accessible can actually make use of it. Instead of hacking drivers to make use of different memory allocation strategies required by unrelated devices, we should instead fix these problems in a proper, scalable way. -- Kind regards, Sakari Ailus e-mail: sakari.ailus@xxxxxx XMPP: sailus@xxxxxxxxxxxxxx -- 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
