Re: [PATCH v4 2/2] media: iris: add support for vbv delay

[Dmitry Baryshkov]

On Sun, Sep 27, 2026 at 09:27:46AM +0530, Sachin Kumar Garg wrote:
> Add the VBV_DELAY instance capability for the HFI Gen2 encoder,
> exposed to userspace via V4L2_CID_MPEG_VIDEO_VBV_DELAY and mapped to
> HFI_PROP_VBV_DELAY through a new iris_set_vbv_delay(). The property
> is only meaningful for CBR rate-control modes.
> 
> Low VBV delay values (34-100 ms) require the encoder to run
> with a single video pipe, so extend iris_set_pipe() to force
> work_route to 1 whenever the configured VBV_DELAY falls in that
> range.
> 
> Reviewed-by: Vikash Garodia <vikash.garodia@xxxxxxxxxxxxxxxx>
> Signed-off-by: Sachin Kumar Garg <sachin.garg@xxxxxxxxxxxxxxxx>
> ---
>  drivers/media/platform/qcom/iris/iris_ctrls.c      | 37 +++++++++++++++++++++-
>  drivers/media/platform/qcom/iris/iris_ctrls.h      |  1 +
>  drivers/media/platform/qcom/iris/iris_hfi_gen2.c   | 12 ++++++-
>  .../platform/qcom/iris/iris_hfi_gen2_defines.h     |  1 +
>  .../platform/qcom/iris/iris_platform_common.h      |  1 +
>  5 files changed, 50 insertions(+), 2 deletions(-)
> 
> @@ -541,8 +545,19 @@ int iris_set_stage(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id
>  int iris_set_pipe(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id)
>  {
>  	const struct iris_hfi_session_ops *hfi_ops = inst->hfi_session_ops;
> -	u32 work_route = inst->fw_caps[PIPE].value;
> +	u32 work_route = inst->fw_caps[PIPE].max;

Why is being set to the max value instead of using the .value?

>  	u32 hfi_id = inst->fw_caps[cap_id].hfi_id;
> +	u32 vbv_delay;
> +
> +	if (inst->domain == ENCODER &&
> +	    inst->fw_caps[FRAME_RC_ENABLE].value &&
> +	    inst->fw_caps[BITRATE_MODE].value == V4L2_MPEG_VIDEO_BITRATE_MODE_CBR) {
> +		vbv_delay = inst->fw_caps[VBV_DELAY].value;
> +		if (vbv_delay >= 34 && vbv_delay <= 100)
> +			work_route = 1;
> +	}
> +
> +	inst->fw_caps[PIPE].value = work_route;
>  
>  	return hfi_ops->session_set_property(inst, hfi_id,
>  					     HFI_HOST_FLAGS_NONE,
-- 
With best wishes
Dmitry