From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx08-00178001.pphosted.com ([91.207.212.93]:27352 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750827AbdAJIzW (ORCPT ); Tue, 10 Jan 2017 03:55:22 -0500 From: Vincent ABRIOU To: Laurent Pinchart 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: Tue, 10 Jan 2017 08:55:16 +0000 Message-ID: <93a7f73c-0c0f-64cb-5918-e86add84b006@st.com> References: <1475494036-18208-1-git-send-email-vincent.abriou@st.com> <5308977.1AOWxa0Moe@avalon> <3193570.QBsjjzBjh2@avalon> In-Reply-To: <3193570.QBsjjzBjh2@avalon> Content-Language: en-US Content-Type: text/plain; charset="Windows-1252" Content-ID: <3BFB271831469540A9CA586EDE0889EA@st.com> Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-media-owner@vger.kernel.org List-ID: Hi Laurent, On 01/09/2017 05:59 PM, Laurent Pinchart wrote: > 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 ? > It is not a gstreamer issue. It is the way it has been decided to work. Waylandsink accept DMABUF contiguous buffer but it does not have its own buffer pool. Vincent >>>> 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(-) >