Re: [PATCH] media: venus: add support for selection rectangles

[mgottam]

On 2018-11-02 03:16, Tomasz Figa wrote:
> On Fri, Nov 2, 2018 at 12:02 AM Stanimir Varbanov
> <stanimir.varbanov@xxxxxxxxxx> wrote:
> > Hi Malathi,
> >
> > On 11/1/18 3:10 PM, mgottam@xxxxxxxxxxxxxx wrote:
> > > On 2018-10-16 15:11, Stanimir Varbanov wrote:
> > >> Hi Malathi,
> > >>
> > >> On 10/09/2018 10:53 AM, Malathi Gottam wrote:
> > >>> Handles target type crop by setting the new active rectangle
> > >>> to hardware. The new rectangle should be within YUV size.
> > >>>
> > >>> Signed-off-by: Malathi Gottam <mgottam@xxxxxxxxxxxxxx>
> > >>> ---
> > >>>  drivers/media/platform/qcom/venus/venc.c | 19 +++++++++++++++++--
> > >>>  1 file changed, 17 insertions(+), 2 deletions(-)
> > >>>
> > >>> diff --git a/drivers/media/platform/qcom/venus/venc.c
> > >>> b/drivers/media/platform/qcom/venus/venc.c
> > >>> index 3f50cd0..754c19a 100644
> > >>> --- a/drivers/media/platform/qcom/venus/venc.c
> > >>> +++ b/drivers/media/platform/qcom/venus/venc.c
> > >>> @@ -478,16 +478,31 @@ static int venc_g_fmt(struct file *file, void
> > >>> *fh, struct v4l2_format *f)
> > >>>  venc_s_selection(struct file *file, void *fh, struct v4l2_selection *s)
> > >>>  {
> > >>>      struct venus_inst *inst = to_inst(file);
> > >>> +    int ret;
> > >>> +    u32 buftype;
> > >>>
> > >>>      if (s->type != V4L2_BUF_TYPE_VIDEO_OUTPUT)
> > >>>          return -EINVAL;
> > >>>
> > >>>      switch (s->target) {
> > >>>      case V4L2_SEL_TGT_CROP:
> > >>> -        if (s->r.width != inst->out_width ||
> > >>> -            s->r.height != inst->out_height ||
> > >>> +        if (s->r.width > inst->out_width ||
> > >>> +            s->r.height > inst->out_height ||
> > >>>              s->r.top != 0 || s->r.left != 0)
> > >>>              return -EINVAL;
>
> Note that returning -EINVAL is not what VIDIOC_S_SELECTION should do 
> here.
>
> As per the general V4L2 spec [1], VIDIOC_S_SELECTION is expected to
> adjust the crop rectangle "as close as possible to the requested one".
> In this case that would likely mean something like this:
>
> if (s->r.left != 0) {
>     s->r.width += s->r.left;
>     s->r.left = 0;
> }
>
> if (s->r.top != 0) {
>     s->r.height += s->r.top;
>     s->r.top = 0;
> }
>
> if (s->r.width > inst->out_width)
>     s->r.width = inst->out_width;
>
> if (s->r.height > inst->out_height)
>     s->r.height = inst->out_height;
>
> [1]
> https://www.kernel.org/doc/html/latest/media/uapi/v4l/vidioc-g-selection.html

Yes Tomasz, I overlooked the spec that we cannot return EINVAL in this 
case.

I will make the necessary changes and update the new patch.
> > >>> +        if (s->r.width != inst->width ||
> > >>> +            s->r.height != inst->height) {
> > >>> +            buftype = HFI_BUFFER_OUTPUT;
> > >>> +            ret = venus_helper_set_output_resolution(inst,
> > >>> +                                 s->r.width,
> > >>> +                                 s->r.height,
> > >>> +                                 buftype);
> > >>
> > >> I'm afraid that set_output_resolution cannot be called at any time. Do
> > >> you think we can set it after start_session?
> > >
> > > Yes Stan, we can set output_resolution after the session has been
> > > initialization.
> > > As per the spec, this call s_selection is an optional step under
> > > Initialization
> > > procedure of encoder even before we request buffers.

Setting this output resolution here I feel it as a repetition as we
have this width and height set to firmware as a part of 
VIDIOC_REQBUFS().
So updating the selection rectangle would be sufficient in this case.

> > What spec you are referring to? The spec for the encoders [1] or
> > something else.
>
> For our convenience, Hans was nice enough to host a compiled version 
> at:
> https://hverkuil.home.xs4all.nl/request-api/uapi/v4l/dev-encoder.html
>
> Best regards,
> Tomasz