From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-vb0-f46.google.com ([209.85.212.46]:43944 "EHLO mail-vb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754126Ab2GaMqp (ORCPT ); Tue, 31 Jul 2012 08:46:45 -0400 Received: by vbbff1 with SMTP id ff1so5686116vbb.19 for ; Tue, 31 Jul 2012 05:46:44 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <201207311411.06974.hverkuil@xs4all.nl> References: <1339684349-28882-1-git-send-email-t.stanislaws@samsung.com> <201207310833.56566.hverkuil@xs4all.nl> <36319543.mdnBULUSen@avalon> <201207311411.06974.hverkuil@xs4all.nl> Date: Tue, 31 Jul 2012 07:46:44 -0500 Message-ID: Subject: Re: [PATCHv2 3/9] v4l: add buffer exporting via dmabuf From: Rob Clark To: Hans Verkuil Cc: Laurent Pinchart , Tomasz Stanislawski , linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, airlied@redhat.com, m.szyprowski@samsung.com, kyungmin.park@samsung.com, sumit.semwal@ti.com, daeinki@gmail.com, daniel.vetter@ffwll.ch, pawel@osciak.com, linaro-mm-sig@lists.linaro.org, remi@remlab.net, subashrp@gmail.com, mchehab@redhat.com, g.liakhovetski@gmx.de Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-media-owner@vger.kernel.org List-ID: On Tue, Jul 31, 2012 at 7:11 AM, Hans Verkuil wrote: >> > For that matter, wouldn't it be useful to support exporting a userptr buffer >> > at some point in the future? >> >> Shouldn't USERPTR usage be discouraged once we get dma-buf support ? > > Why? It's perfectly fine to use it and it's not going away. > > I'm not saying that we should support exporting a userptr buffer as a dmabuf fd, > but I'm just wondering if that is possible at all and how difficult it would be. it seems not terribly safe, since you don't really have much control over where the memory comes from w/ userptr. I'm more in favor of discouraging usage of userptr BR, -R