Hi Sakari, On 01/11/2017 12:03 PM, Sakari Ailus wrote: > 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? > Yes, drm driver that does not have mmu needs to have contiguous buffers. > 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. > Scalable way? Like central allocator? Vincent-- 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
