Re: [PATCH] media: iris: Fix FPS calculation and VPP FW overhead

[Dmitry Baryshkov]

On Tue, Jun 02, 2026 at 10:01:24PM +0100, Bryan O'Donoghue wrote:
> Use div_u64() instead of mult_fract as u64 operator division fails on 32 bit
> systems which don't link against libgcc.
> 
> Fixes: 5c66647a5c3e ("media: iris: add FPS calculation and VPP FW overhead in frequency formula")
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Closes: https://lore.kernel.org/oe-kbuild-all/202606030132.qnBXVDkM-lkp@xxxxxxxxx/
> Signed-off-by: Bryan O'Donoghue <bod@xxxxxxxxxx>
> ---
> Quick fix for u32 bit division error in -next.
> ---
>  drivers/media/platform/qcom/iris/iris_vpu_common.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/media/platform/qcom/iris/iris_vpu_common.c b/drivers/media/platform/qcom/iris/iris_vpu_common.c
> index 5a85568c5ee1c..37dbfe433a085 100644
> --- a/drivers/media/platform/qcom/iris/iris_vpu_common.c
> +++ b/drivers/media/platform/qcom/iris/iris_vpu_common.c
> @@ -444,7 +444,7 @@ u64 iris_vpu3x_vpu4x_calculate_frequency(struct iris_inst *inst, size_t data_siz
>  
>  	/* 1.05 is VPP FW overhead */
>  	if (inst->fw_caps[STAGE].value == STAGE_2)
> -		vpp_cycles += mult_frac(vpp_cycles, 5, 100);
> +		vpp_cycles += div_u64(vpp_cycles * 5, 100);


Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx>

> 

-- 
With best wishes
Dmitry