Hi Guennadi, What's your opinion on this? I was intended to complement the PREPARE_BUF documentation. On Thu, Sep 01, 2011 at 02:08:56PM +0300, Sakari Ailus wrote: > Add note to documentation of VIDIOC_PREPARE_BUF that the preparation done by > the IOCTL may include locking buffers to system memory and creating DMA > mappings for them. > > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxx> > --- > .../DocBook/media/v4l/vidioc-prepare-buf.xml | 8 +++++--- > 1 files changed, 5 insertions(+), 3 deletions(-) > > diff --git a/Documentation/DocBook/media/v4l/vidioc-prepare-buf.xml b/Documentation/DocBook/media/v4l/vidioc-prepare-buf.xml > index 509e752..7177c2f 100644 > --- a/Documentation/DocBook/media/v4l/vidioc-prepare-buf.xml > +++ b/Documentation/DocBook/media/v4l/vidioc-prepare-buf.xml > @@ -52,9 +52,11 @@ > <constant>VIDIOC_PREPARE_BUF</constant> ioctl to pass ownership of the buffer > to the driver before actually enqueuing it, using the > <constant>VIDIOC_QBUF</constant> ioctl, and to prepare it for future I/O. > -Such preparations may include cache invalidation or cleaning. Performing them > -in advance saves time during the actual I/O. In case such cache operations are > -not required, the application can use one of > +Such preparations may include locking the buffer to system memory and > +creating DMA mapping for it (on the first time > +<constant>VIDIOC_PREPARE_BUF</constant> is called), cache invalidation or > +cleaning. Performing them in advance saves time during the actual I/O. In > +case such cache operations are not required, the application can use one of > <constant>V4L2_BUF_FLAG_NO_CACHE_INVALIDATE</constant> and > <constant>V4L2_BUF_FLAG_NO_CACHE_CLEAN</constant> flags to skip the respective > step.</para> > -- > 1.7.2.5 > > -- > 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 -- Sakari Ailus e-mail: sakari.ailus@xxxxxx jabber/XMPP/Gmail: sailus@xxxxxxxxxxxxxx -- 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
