From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from galahad.ideasonboard.com ([185.26.127.97]:35290 "EHLO galahad.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751054AbdAIQ7B (ORCPT ); Mon, 9 Jan 2017 11:59:01 -0500 From: Laurent Pinchart To: Vincent ABRIOU Cc: "linux-media@vger.kernel.org" , Benjamin Gaignard , Hugues FRUCHET , Jean Christophe TROTIN , Nicolas Dufresne Subject: Re: [media] uvcvideo: support for contiguous DMA buffers Date: Mon, 09 Jan 2017 18:59:09 +0200 Message-ID: <3193570.QBsjjzBjh2@avalon> In-Reply-To: References: <1475494036-18208-1-git-send-email-vincent.abriou@st.com> <5308977.1AOWxa0Moe@avalon> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-media-owner@vger.kernel.org List-ID: Hi Vincent, (CC'ing Nicolas) On Monday 09 Jan 2017 15:49:00 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. Isn't that a gstreamer issue ? > >> Add the "allocators" module parameter option to let uvcvideo use the > >> dma-contig instead of vmalloc. > >> > >> Signed-off-by: Vincent Abriou > >> --- > >> > >> Documentation/media/v4l-drivers/uvcvideo.rst | 12 ++++++++++++ > >> drivers/media/usb/uvc/Kconfig | 2 ++ > >> drivers/media/usb/uvc/uvc_driver.c | 3 ++- > >> drivers/media/usb/uvc/uvc_queue.c | 23 ++++++++++++++++++--- > >> drivers/media/usb/uvc/uvcvideo.h | 4 ++-- > >> 5 files changed, 38 insertions(+), 6 deletions(-) -- Regards, Laurent Pinchart