Re: [RFC v2 03/11] vb2: Move cache synchronisation from buffer done to dqbuf handler

Shuah Khan
2017-03-27T21:27:38Z

On Thu, Dec 15, 2016 at 6:24 PM, Laurent Pinchart
<laurent.pinchart+renesas@ideasonboard.com> wrote:
> From: Sakari Ailus <sakari.ailus@linux.intel.com>
>
> The cache synchronisation may be a time consuming operation and thus not
> best performed in an interrupt which is a typical context for
> vb2_buffer_done() calls. This may consume up to tens of ms on some
> machines, depending on the buffer size.
>
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> ---
> Changes since v1:
>
> - Don't rename the 'i' loop counter to 'plane'
> ---
> drivers/media/v4l2-core/videobuf2-core.c | 9 ++++-----
> 1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
> index 8ba48703b189..15a83f338072 100644
> --- a/drivers/media/v4l2-core/videobuf2-core.c
> +++ b/drivers/media/v4l2-core/videobuf2-core.c
> @@ -889,7 +889,6 @@ void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
> {
> struct vb2_queue *q = vb->vb2_queue;
> unsigned long flags;
> - unsigned int plane;
>
> if (WARN_ON(vb->state != VB2_BUF_STATE_ACTIVE))
> return;
> @@ -910,10 +909,6 @@ void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
> dprintk(4, "done processing on buffer %d, state: %d\n",
> vb->index, state);
>
> - /* sync buffers */
> - for (plane = 0; plane < vb->num_planes; ++plane)
> - call_void_memop(vb, finish, vb->planes[plane].mem_priv);
> -
> spin_lock_irqsave(&q->done_lock, flags);
> if (state == VB2_BUF_STATE_QUEUED ||
> state == VB2_BUF_STATE_REQUEUEING) {
> @@ -1571,6 +1566,10 @@ static void __vb2_dqbuf(struct vb2_buffer *vb)
>
> vb->state = VB2_BUF_STATE_DEQUEUED;
>
> + /* sync buffers */
> + for (i = 0; i < vb->num_planes; ++i)
> + call_void_memop(vb, finish, vb->planes[i].mem_priv);
> +

Does this compile?? Where is "i" defined? Looks like it needs to be added
back in.

-- Shuah

> /* unmap DMABUF buffer */
> if (q->memory == VB2_MEMORY_DMABUF)
> for (i = 0; i < vb->num_planes; ++i) {
> --
> Regards,
>
> Laurent Pinchart
>
> --
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