Re: [PATCH v7 10/18] media: iris: skip PIPE if it is not supported by the platform

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [Critical] Missing `PIPE` capability results in a latent division by zero in `iris_vpu3x_vpu4x_calculate_frequency()`.
--

--- Patch [10]: [PATCH v7 10/18] media: iris: skip PIPE if it is not supported by the platform ---
commit 3fc5cca6cb7d8fdca8a5f48a5b724d09591a0347
Author: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

media: iris: skip PIPE if it is not supported by the platform

This commit skips programming the HFI_PROPERTY_PARAM_WORK_ROUTE property
in iris_set_pipe() if the platform lacks the corresponding capability.
This prevents failures on platforms like AR50LT that do not support it.

> diff --git a/drivers/media/platform/qcom/iris/iris_ctrls.c b/drivers/media/platform/qcom/iris/iris_ctrls.c
> index 10e33b8a73f60..33a34573391a4 100644
> --- a/drivers/media/platform/qcom/iris/iris_ctrls.c
> +++ b/drivers/media/platform/qcom/iris/iris_ctrls.c
> @@ -534,6 +534,9 @@ int iris_set_pipe(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id)
>  	u32 work_route = inst->fw_caps[PIPE].value;
>  	u32 hfi_id = inst->fw_caps[cap_id].hfi_id;
>  
> +	if (!hfi_id)
> +		return 0;
> +

[Severity: Critical]
This is a pre-existing issue, but does skipping the PIPE capability here mean
inst->fw_caps[PIPE].value remains 0?

If so, could this cause a division by zero later in the VPU clock calculation?
Looking at iris_vpu3x_vpu4x_calculate_frequency() in iris_vpu_common.c:

drivers/media/platform/qcom/iris/iris_vpu_common.c:iris_vpu3x_vpu4x_calculate_frequency() {
    ...
	vpp_cycles = mult_frac(mbs_per_second, caps->mb_cycles_vpp, (u32)inst->fw_caps[PIPE].value);
    ...
}

Because mult_frac() divides by its third argument without a zero check,
this could result in a fatal division by zero when a userspace application
opens the encoder on a VPU3x/VPU4x platform omitting the PIPE capability.

>  	return hfi_ops->session_set_property(inst, hfi_id,
>  					     HFI_HOST_FLAGS_NONE,
>  					     iris_get_port_info(inst, cap_id),
>  					     HFI_PAYLOAD_U32,
>  					     &work_route, sizeof(u32));
>  }

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260709-iris-ar50lt-v7-0-76af9dd4d1f6@oss.qualcomm.com?part=10