Re: [PATCH v2] media: iris: Retain firmware confirmed video_format across GOP restarts

[Gourav Kumar]

On 9/5/2026 7:27 PM, Vishnu Reddy wrote:
> During speed-based rewind, the client restarts the decoder queues once per
> group of pictures (GOP). This is because playing a GOP-based stream in
> reverse requires decoding each group forward first and then showing its
> frames in reverse order. Each restart makes the driver resend the colour
> info property on the bitstream port, which firmware always treats as a
> sign that the stream's properties may have changed. The driver never
> stored the video_format value that firmware had last confirmed, so it
> resent colour info with a fixed unspecified value instead of the real one,
> and the value firmware received kept differing from what it already had.
> 
> On every restart during rewind, this looked to firmware like a real change
> on the bitstream port, so firmware sent a settings-change notification,
> and the driver treated it as a dynamic resolution change and paused the
> port. The client then removed its buffers and built new ones for a
> resolution that had not actually changed, stalling playback once per GOP.
> 
> Store and send back the same video_format value firmware already confirmed
> so both sides stay in agreement across every restart, avoiding the false
> settings-change notification.
> 
> Signed-off-by: Vishnu Reddy <busanna.reddy@xxxxxxxxxxxxxxxx>
> ---
> Changes in v2:
> - Updated the commit description (Konrad)
> - Link to v1: https://patch.msgid.link/20260901-read_video_format_from_firmware-v1-1-499edea4d200@xxxxxxxxxxxxxxxx
> ---
>  drivers/media/platform/qcom/iris/iris_hfi_common.h        | 1 +
>  drivers/media/platform/qcom/iris/iris_hfi_gen2_command.c  | 3 ++-
>  drivers/media/platform/qcom/iris/iris_hfi_gen2_response.c | 2 ++
>  3 files changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/platform/qcom/iris/iris_hfi_common.h b/drivers/media/platform/qcom/iris/iris_hfi_common.h
> index a27447eb2519..439197e9e199 100644
> --- a/drivers/media/platform/qcom/iris/iris_hfi_common.h
> +++ b/drivers/media/platform/qcom/iris/iris_hfi_common.h
> @@ -141,6 +141,7 @@ struct hfi_subscription_params {
>  	u32	fw_min_count;
>  	u32	pic_order_cnt;
>  	u32	color_info;
> +	u32	video_format;
>  	u32	profile;
>  	u32	level;
>  	u32	tier;
> diff --git a/drivers/media/platform/qcom/iris/iris_hfi_gen2_command.c b/drivers/media/platform/qcom/iris/iris_hfi_gen2_command.c
> index 388a36ff2b07..a43a9d7687ad 100644
> --- a/drivers/media/platform/qcom/iris/iris_hfi_gen2_command.c
> +++ b/drivers/media/platform/qcom/iris/iris_hfi_gen2_command.c
> @@ -358,7 +358,7 @@ static int iris_hfi_gen2_set_colorspace(struct iris_inst *inst, u32 plane)
>  	struct v4l2_pix_format_mplane *pixmp = &inst->fmt_src->fmt.pix_mp;
>  	u32 video_signal_type_present_flag = 0, color_info;
>  	u32 matrix_coeff = HFI_MATRIX_COEFF_RESERVED;
> -	u32 video_format = UNSPECIFIED_COLOR_FORMAT;
> +	u32 video_format = inst_hfi_gen2->src_subcr_params.video_format;
>  	u32 full_range = V4L2_QUANTIZATION_DEFAULT;
>  	u32 transfer_char = HFI_TRANSFER_RESERVED;
>  	u32 port = iris_hfi_gen2_get_port(inst, plane);
> @@ -806,6 +806,7 @@ static int iris_hfi_gen2_session_open(struct iris_inst *inst)
>  
>  	inst_hfi_gen2->ipsc_properties_set = false;
>  	inst_hfi_gen2->opsc_properties_set = false;
> +	inst_hfi_gen2->src_subcr_params.video_format = UNSPECIFIED_COLOR_FORMAT;
>  
>  	inst_hfi_gen2->packet = kzalloc(4096, GFP_KERNEL);
>  	if (!inst_hfi_gen2->packet)
> diff --git a/drivers/media/platform/qcom/iris/iris_hfi_gen2_response.c b/drivers/media/platform/qcom/iris/iris_hfi_gen2_response.c
> index 8c2644c7f6e8..8b1ff253a560 100644
> --- a/drivers/media/platform/qcom/iris/iris_hfi_gen2_response.c
> +++ b/drivers/media/platform/qcom/iris/iris_hfi_gen2_response.c
> @@ -581,6 +581,8 @@ static void iris_hfi_gen2_read_input_subcr_params(struct iris_inst *inst)
>  	full_range = (subsc_params.color_info & 0x2000000) >> 25;
>  	video_signal_type_present_flag =
>  		(subsc_params.color_info & 0x20000000) >> 29;
> +	inst_hfi_gen2->src_subcr_params.video_format =
> +		(subsc_params.color_info & 0x1C000000) >> 26;
>  
>  	pixmp_op->colorspace = V4L2_COLORSPACE_DEFAULT;
>  	pixmp_op->xfer_func = V4L2_XFER_FUNC_DEFAULT;
> 
> ---
> base-commit: 9d80aa4617b32f5054c5aa471d06b66704854935
> change-id: 20260905-read_video_format_from_firmware-ecbb322a6fd4
> 
> Best regards,
> --  
> Vishnu Reddy <busanna.reddy@xxxxxxxxxxxxxxxx>

Tested-by: Gourav Kumar <gourav.kumar@xxxxxxxxxxxxxxxx>