Re: [PATCH] media: venus: add support for key frame

[mgottam]

On 2018-10-23 08:37, Tomasz Figa wrote:
> On Mon, Oct 22, 2018 at 3:15 PM Alexandre Courbot 
> <acourbot@xxxxxxxxxxxx> wrote:
> > On Fri, Oct 12, 2018 at 5:10 PM Stanimir Varbanov
> > <stanimir.varbanov@xxxxxxxxxx> wrote:
> > >
> > >
> > >
> > > On 10/12/2018 11:06 AM, Alexandre Courbot wrote:
> > > > On Fri, Oct 12, 2018 at 4:37 PM Stanimir Varbanov
> > > > <stanimir.varbanov@xxxxxxxxxx> wrote:
> > > >>
> > > >> Hi Alex,
> > > >>
> > > >> On 10/12/2018 08:26 AM, Alexandre Courbot wrote:
> > > >>> On Tue, Oct 9, 2018 at 4:54 PM Malathi Gottam <mgottam@xxxxxxxxxxxxxx> wrote:
> > > >>>>
> > > >>>> When client requests for a keyframe, set the property
> > > >>>> to hardware to generate the sync frame.
> > > >>>>
> > > >>>> Signed-off-by: Malathi Gottam <mgottam@xxxxxxxxxxxxxx>
> > > >>>> ---
> > > >>>>  drivers/media/platform/qcom/venus/venc_ctrls.c | 13 +++++++++++++
> > > >>>>  1 file changed, 13 insertions(+)
> > > >>>>
> > > >>>> diff --git a/drivers/media/platform/qcom/venus/venc_ctrls.c b/drivers/media/platform/qcom/venus/venc_ctrls.c
> > > >>>> index 45910172..f332c8e 100644
> > > >>>> --- a/drivers/media/platform/qcom/venus/venc_ctrls.c
> > > >>>> +++ b/drivers/media/platform/qcom/venus/venc_ctrls.c
> > > >>>> @@ -81,6 +81,8 @@ static int venc_op_s_ctrl(struct v4l2_ctrl *ctrl)
> > > >>>>         struct venc_controls *ctr = &inst->controls.enc;
> > > >>>>         u32 bframes;
> > > >>>>         int ret;
> > > >>>> +       void *ptr;
> > > >>>> +       u32 ptype;
> > > >>>>
> > > >>>>         switch (ctrl->id) {
> > > >>>>         case V4L2_CID_MPEG_VIDEO_BITRATE_MODE:
> > > >>>> @@ -173,6 +175,14 @@ static int venc_op_s_ctrl(struct v4l2_ctrl *ctrl)
> > > >>>>
> > > >>>>                 ctr->num_b_frames = bframes;
> > > >>>>                 break;
> > > >>>> +       case V4L2_CID_MPEG_VIDEO_FORCE_KEY_FRAME:
> > > >>>> +               ptype = HFI_PROPERTY_CONFIG_VENC_REQUEST_SYNC_FRAME;
> > > >>>> +               ret = hfi_session_set_property(inst, ptype, ptr);
> > > >>>
> > > >>> The test bot already said it, but ptr is passed to
> > > >>> hfi_session_set_property() uninitialized. And as can be expected the
> > > >>> call returns -EINVAL on my board.
> > > >>>
> > > >>> Looking at other uses of HFI_PROPERTY_CONFIG_VENC_REQUEST_SYNC_FRAME I
> > > >>> see that the packet sent to the firmware does not have room for an
> > > >>> argument, so I tried to pass NULL but got the same result.
> > > >>
> > > >> yes, because pdata cannot be NULL. I'd suggest to make a pointer to
> > > >> struct hfi_enable and pass it to the set_property function.
> > > >
> > > > FWIW I also tried doing this and got the same error, strange...
> > > >
> > >
> > > OK, when you calling the v4l control? It makes sense when you calling
> > > it, because set_property checks does the session is on START state (i.e.
> > > streamon on both queues).
> >
> > Do you mean that the property won't be actually applied unless both
> > queues are streaming? In that case maybe it would make sense for the
> > driver to save controls set before that and apply them when the
> > conditions allow them to be effective?
>
> Right. The driver cannot just drop a control setting on the floor if
> it's not ready to apply it.
>
> However, the V4L2 control framework already provides a tool to handle 
> this:
>  - the driver can ignore any .s_ctrl() calls when it can't apply the 
> controls,
>  - the driver must call v4l2_ctrl_handler_setup() when it initialized
> the hardware, so that all the control values are applied in one go.
>
> Best regards,
> Tomasz
Yes V4L2 control framework validates the ctrls before being set.

But these controls are initialized before session initialization. So 
s_ctrl tries to set property 
"HFI_PROPERTY_CONFIG_VENC_REQUEST_SYNC_FRAME" as a part of initializing 
all controls(session still in UNINIT state). But this is not any client 
request.

So we can keep a check to
1. ensure that its client requesting sync frame and
2. session in START state (both planes are streaming)

I will update the patch with these changes.