From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: [PATCH] dma-buf: Update docs for SYNC ioctl Date: Mon, 21 Mar 2016 18:14:05 +0100 Message-ID: <20160321171405.GP28483@phenom.ffwll.local> References: <1458546705-3564-1-git-send-email-daniel.vetter@ffwll.ch> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: driverdev-devel-bounces@linuxdriverproject.org Sender: "devel" To: David Herrmann Cc: devel@driverdev.osuosl.org, Hans Verkuil , Daniel Vetter , Daniel Vetter , Intel Graphics Development , DRI Development , Chris Wilson , linaro-mm-sig@lists.linaro.org, Tiago Vignatti , =?iso-8859-1?Q?St=E9phane?= Marchesin , Sumit Semwal , linux-media@vger.kernel.org List-Id: dri-devel@lists.freedesktop.org On Mon, Mar 21, 2016 at 01:26:58PM +0100, David Herrmann wrote: > Hi > = > On Mon, Mar 21, 2016 at 8:51 AM, Daniel Vetter w= rote: > > Just a bit of wording polish plus mentioning that it can fail and must > > be restarted. > > > > Requested by Sumit. > > > > v2: Fix them typos (Hans). > > > > Cc: Chris Wilson > > Cc: Tiago Vignatti > > Cc: St=E9phane Marchesin > > Cc: David Herrmann > > Cc: Sumit Semwal > > Cc: Daniel Vetter > > CC: linux-media@vger.kernel.org > > Cc: dri-devel@lists.freedesktop.org > > Cc: linaro-mm-sig@lists.linaro.org > > Cc: intel-gfx@lists.freedesktop.org > > Cc: devel@driverdev.osuosl.org > > Cc: Hans Verkuil > > Acked-by: Sumit Semwal > > Signed-off-by: Daniel Vetter > > --- > > Documentation/dma-buf-sharing.txt | 11 ++++++----- > > drivers/dma-buf/dma-buf.c | 2 +- > > 2 files changed, 7 insertions(+), 6 deletions(-) > > > > diff --git a/Documentation/dma-buf-sharing.txt b/Documentation/dma-buf-= sharing.txt > > index 32ac32e773e1..ca44c5820585 100644 > > --- a/Documentation/dma-buf-sharing.txt > > +++ b/Documentation/dma-buf-sharing.txt > > @@ -352,7 +352,8 @@ Being able to mmap an export dma-buf buffer object = has 2 main use-cases: > > > > No special interfaces, userspace simply calls mmap on the dma-buf f= d, making > > sure that the cache synchronization ioctl (DMA_BUF_IOCTL_SYNC) is *= always* > > - used when the access happens. This is discussed next paragraphs. > > + used when the access happens. Note that DMA_BUF_IOCTL_SYNC can fail= with > > + -EAGAIN or -EINTR, in which case it must be restarted. > = > What is "restart on EAGAIN" supposed to mean? Or more generally, what > does EAGAIN tell the caller? Do what drmIoctl does essentially. while (ret =3D=3D -1 && (errno =3D=3D EAGAIN || errno =3D=3D EINTR) ret =3D ioctl(); Typed from memery, too lazy to look it up in the source ;-) I'm trying to sell the idea of a real dma-buf manpage to Sumit, we should clarify this in detail there. -Daniel -- = Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch