iris_venc_s_param() uses do_div to divide two 64 bits operators, this is
wrong. Luckily for us, both of the operators fit in 32 bits, so we can use
a normal division.
Now that we are at it, mark the fps smaller than 1 as invalid, the code
does not seem to handle them properly.
The following cocci warning is fixed with this patch:
./platform/qcom/iris/iris_venc.c:378:1-7: WARNING: do_div() does a 64-by-32 division, please consider using div64_u64 instead
Fixes: 4ff586ff28e3 ("media: iris: Add support for G/S_PARM for encoder video device")
Reviewed-by: Dikshita Agarwal <dikshita.agarwal@oss.qualcomm.com>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
drivers/media/platform/qcom/iris/iris_venc.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/media/platform/qcom/iris/iris_venc.c b/drivers/media/platform/qcom/iris/iris_venc.c
index 5830eba93c68b27fa9db87bac63a691eaca338d2..730f2aa1a83b2f4f90227ab9a7e04aee7c2c3cfe 100644
--- a/drivers/media/platform/qcom/iris/iris_venc.c
+++ b/drivers/media/platform/qcom/iris/iris_venc.c
@@ -408,11 +408,10 @@ int iris_venc_s_param(struct iris_inst *inst, struct v4l2_streamparm *s_parm)
us_per_frame = timeperframe->numerator * (u64)USEC_PER_SEC;
do_div(us_per_frame, timeperframe->denominator);
- if (!us_per_frame)
+ if (!us_per_frame || us_per_frame > USEC_PER_SEC)
return -EINVAL;
- fps = (u64)USEC_PER_SEC;
- do_div(fps, us_per_frame);
+ fps = USEC_PER_SEC / (u32)us_per_frame;
if (fps > max_rate) {
ret = -ENOMEM;
goto reset_rate;
--
2.52.0.158.g65b55ccf14-goog
On Wed, Dec 03, 2025 at 08:55:36AM +0000, Ricardo Ribalda wrote:
> iris_venc_s_param() uses do_div to divide two 64 bits operators, this is
> wrong. Luckily for us, both of the operators fit in 32 bits, so we can use
> a normal division.
>
> Now that we are at it, mark the fps smaller than 1 as invalid, the code
> does not seem to handle them properly.
>
> The following cocci warning is fixed with this patch:
> ./platform/qcom/iris/iris_venc.c:378:1-7: WARNING: do_div() does a 64-by-32 division, please consider using div64_u64 instead
>
> Fixes: 4ff586ff28e3 ("media: iris: Add support for G/S_PARM for encoder video device")
> Reviewed-by: Dikshita Agarwal <dikshita.agarwal@oss.qualcomm.com>
> Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> ---
> drivers/media/platform/qcom/iris/iris_venc.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/media/platform/qcom/iris/iris_venc.c b/drivers/media/platform/qcom/iris/iris_venc.c
> index 5830eba93c68b27fa9db87bac63a691eaca338d2..730f2aa1a83b2f4f90227ab9a7e04aee7c2c3cfe 100644
> --- a/drivers/media/platform/qcom/iris/iris_venc.c
> +++ b/drivers/media/platform/qcom/iris/iris_venc.c
> @@ -408,11 +408,10 @@ int iris_venc_s_param(struct iris_inst *inst, struct v4l2_streamparm *s_parm)
> us_per_frame = timeperframe->numerator * (u64)USEC_PER_SEC;
> do_div(us_per_frame, timeperframe->denominator);
>
> - if (!us_per_frame)
> + if (!us_per_frame || us_per_frame > USEC_PER_SEC)
> return -EINVAL;
>
> - fps = (u64)USEC_PER_SEC;
> - do_div(fps, us_per_frame);
> + fps = USEC_PER_SEC / (u32)us_per_frame;
Can we replace this with:
fps = timeperframe->denominator / timeperframe->numerator ?
> if (fps > max_rate) {
> ret = -ENOMEM;
> goto reset_rate;
>
> --
> 2.52.0.158.g65b55ccf14-goog
>
--
With best wishes
Dmitry
On Sat, 6 Dec 2025 at 13:06, Dmitry Baryshkov
<dmitry.baryshkov@oss.qualcomm.com> wrote:
>
> On Wed, Dec 03, 2025 at 08:55:36AM +0000, Ricardo Ribalda wrote:
> > iris_venc_s_param() uses do_div to divide two 64 bits operators, this is
> > wrong. Luckily for us, both of the operators fit in 32 bits, so we can use
> > a normal division.
> >
> > Now that we are at it, mark the fps smaller than 1 as invalid, the code
> > does not seem to handle them properly.
> >
> > The following cocci warning is fixed with this patch:
> > ./platform/qcom/iris/iris_venc.c:378:1-7: WARNING: do_div() does a 64-by-32 division, please consider using div64_u64 instead
> >
> > Fixes: 4ff586ff28e3 ("media: iris: Add support for G/S_PARM for encoder video device")
> > Reviewed-by: Dikshita Agarwal <dikshita.agarwal@oss.qualcomm.com>
> > Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> > ---
> > drivers/media/platform/qcom/iris/iris_venc.c | 5 ++---
> > 1 file changed, 2 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/media/platform/qcom/iris/iris_venc.c b/drivers/media/platform/qcom/iris/iris_venc.c
> > index 5830eba93c68b27fa9db87bac63a691eaca338d2..730f2aa1a83b2f4f90227ab9a7e04aee7c2c3cfe 100644
> > --- a/drivers/media/platform/qcom/iris/iris_venc.c
> > +++ b/drivers/media/platform/qcom/iris/iris_venc.c
> > @@ -408,11 +408,10 @@ int iris_venc_s_param(struct iris_inst *inst, struct v4l2_streamparm *s_parm)
> > us_per_frame = timeperframe->numerator * (u64)USEC_PER_SEC;
> > do_div(us_per_frame, timeperframe->denominator);
> >
> > - if (!us_per_frame)
> > + if (!us_per_frame || us_per_frame > USEC_PER_SEC)
> > return -EINVAL;
> >
> > - fps = (u64)USEC_PER_SEC;
> > - do_div(fps, us_per_frame);
> > + fps = USEC_PER_SEC / (u32)us_per_frame;
>
> Can we replace this with:
>
> fps = timeperframe->denominator / timeperframe->numerator ?
Yep, I believe you are correct
I will send a new version soon.
>
> > if (fps > max_rate) {
> > ret = -ENOMEM;
> > goto reset_rate;
> >
> > --
> > 2.52.0.158.g65b55ccf14-goog
> >
>
> --
> With best wishes
> Dmitry
--
Ricardo Ribalda
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