2019-11-19 13:38:32

by Benjamin GAIGNARD

Subject: [PATCH] drm/rect: remove useless call to clamp_t

Clamping a value between INT_MIN and INT_MAX always return the value itself
and generate warnings when compiling with W=1.

Signed-off-by: Benjamin Gaignard <[email protected]>
---
drivers/gpu/drm/drm_rect.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_rect.c b/drivers/gpu/drm/drm_rect.c
index b8363aaa9032..681f1fd09357 100644
--- a/drivers/gpu/drm/drm_rect.c
+++ b/drivers/gpu/drm/drm_rect.c
@@ -89,7 +89,7 @@ bool drm_rect_clip_scaled(struct drm_rect *src, struct drm_rect *dst,
u32 new_src_w = clip_scaled(drm_rect_width(src),
drm_rect_width(dst), diff);

- src->x1 = clamp_t(int64_t, src->x2 - new_src_w, INT_MIN, INT_MAX);
+ src->x1 = src->x2 - new_src_w;
dst->x1 = clip->x1;
}
diff = clip->y1 - dst->y1;
@@ -97,7 +97,7 @@ bool drm_rect_clip_scaled(struct drm_rect *src, struct drm_rect *dst,
u32 new_src_h = clip_scaled(drm_rect_height(src),
drm_rect_height(dst), diff);

- src->y1 = clamp_t(int64_t, src->y2 - new_src_h, INT_MIN, INT_MAX);
+ src->y1 = src->y2 - new_src_h;
dst->y1 = clip->y1;
}
diff = dst->x2 - clip->x2;
@@ -105,7 +105,7 @@ bool drm_rect_clip_scaled(struct drm_rect *src, struct drm_rect *dst,
u32 new_src_w = clip_scaled(drm_rect_width(src),
drm_rect_width(dst), diff);

- src->x2 = clamp_t(int64_t, src->x1 + new_src_w, INT_MIN, INT_MAX);
+ src->x2 = src->x1 + new_src_w;
dst->x2 = clip->x2;
}
diff = dst->y2 - clip->y2;
@@ -113,7 +113,7 @@ bool drm_rect_clip_scaled(struct drm_rect *src, struct drm_rect *dst,
u32 new_src_h = clip_scaled(drm_rect_height(src),
drm_rect_height(dst), diff);

- src->y2 = clamp_t(int64_t, src->y1 + new_src_h, INT_MIN, INT_MAX);
+ src->y2 = src->y1 + new_src_h;
dst->y2 = clip->y2;
}

--
2.15.0

2019-11-20 17:16:00

by Jani Nikula

Subject: Re: [PATCH] drm/rect: remove useless call to clamp_t

On Tue, 19 Nov 2019, Benjamin Gaignard <[email protected]> wrote:
> Clamping a value between INT_MIN and INT_MAX always return the value itself
> and generate warnings when compiling with W=1.

Does that hold for 32-bit too?

BR,
Jani.

>
> Signed-off-by: Benjamin Gaignard <[email protected]>
> ---
> drivers/gpu/drm/drm_rect.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_rect.c b/drivers/gpu/drm/drm_rect.c
> index b8363aaa9032..681f1fd09357 100644
> --- a/drivers/gpu/drm/drm_rect.c
> +++ b/drivers/gpu/drm/drm_rect.c
> @@ -89,7 +89,7 @@ bool drm_rect_clip_scaled(struct drm_rect *src, struct drm_rect *dst,
> u32 new_src_w = clip_scaled(drm_rect_width(src),
> drm_rect_width(dst), diff);
>
> - src->x1 = clamp_t(int64_t, src->x2 - new_src_w, INT_MIN, INT_MAX);
> + src->x1 = src->x2 - new_src_w;
> dst->x1 = clip->x1;
> }
> diff = clip->y1 - dst->y1;
> @@ -97,7 +97,7 @@ bool drm_rect_clip_scaled(struct drm_rect *src, struct drm_rect *dst,
> u32 new_src_h = clip_scaled(drm_rect_height(src),
> drm_rect_height(dst), diff);
>
> - src->y1 = clamp_t(int64_t, src->y2 - new_src_h, INT_MIN, INT_MAX);
> + src->y1 = src->y2 - new_src_h;
> dst->y1 = clip->y1;
> }
> diff = dst->x2 - clip->x2;
> @@ -105,7 +105,7 @@ bool drm_rect_clip_scaled(struct drm_rect *src, struct drm_rect *dst,
> u32 new_src_w = clip_scaled(drm_rect_width(src),
> drm_rect_width(dst), diff);
>
> - src->x2 = clamp_t(int64_t, src->x1 + new_src_w, INT_MIN, INT_MAX);
> + src->x2 = src->x1 + new_src_w;
> dst->x2 = clip->x2;
> }
> diff = dst->y2 - clip->y2;
> @@ -113,7 +113,7 @@ bool drm_rect_clip_scaled(struct drm_rect *src, struct drm_rect *dst,
> u32 new_src_h = clip_scaled(drm_rect_height(src),
> drm_rect_height(dst), diff);
>
> - src->y2 = clamp_t(int64_t, src->y1 + new_src_h, INT_MIN, INT_MAX);
> + src->y2 = src->y1 + new_src_h;
> dst->y2 = clip->y2;
> }

--
Jani Nikula, Intel Open Source Graphics Center

2019-11-20 17:20:42

by Ville Syrjälä

Subject: Re: [PATCH] drm/rect: remove useless call to clamp_t

On Tue, Nov 19, 2019 at 02:34:35PM +0100, Benjamin Gaignard wrote:
> Clamping a value between INT_MIN and INT_MAX always return the value itself
> and generate warnings when compiling with W=1.
>
> Signed-off-by: Benjamin Gaignard <[email protected]>
> ---
> drivers/gpu/drm/drm_rect.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_rect.c b/drivers/gpu/drm/drm_rect.c
> index b8363aaa9032..681f1fd09357 100644
> --- a/drivers/gpu/drm/drm_rect.c
> +++ b/drivers/gpu/drm/drm_rect.c
> @@ -89,7 +89,7 @@ bool drm_rect_clip_scaled(struct drm_rect *src, struct drm_rect *dst,
> u32 new_src_w = clip_scaled(drm_rect_width(src),
> drm_rect_width(dst), diff);

Hmm. I think we borked this a bit when introducing clip_scaled().
'diff' can exceed dst width here so clip_scaled() should be able to
return a negative value.

Probably we should make this more consistent and do something like:
diff = clip->x1 - dst->x1;
if (diff > 0) {
- u32 new_src_w = clip_scaled(drm_rect_width(src),
- drm_rect_width(dst), diff);
+ int dst_w, new_src_w;

- src->x1 = clamp_t(int64_t, src->x2 - new_src_w, INT_MIN, INT_MAX);
- dst->x1 = clip->x1;
+ dst_w = drm_rect_width(dst);
+ diff = min(diff, dst_w);
+ new_src_w = clip_scaled(drm_rect_width(src), dst_w, diff);
+
+ src->x1 = src->x2 - new_src_w;
+ dst->x1 += diff;
}

etc.

>
> - src->x1 = clamp_t(int64_t, src->x2 - new_src_w, INT_MIN, INT_MAX);
> + src->x1 = src->x2 - new_src_w;
> dst->x1 = clip->x1;
> }
> diff = clip->y1 - dst->y1;
> @@ -97,7 +97,7 @@ bool drm_rect_clip_scaled(struct drm_rect *src, struct drm_rect *dst,
> u32 new_src_h = clip_scaled(drm_rect_height(src),
> drm_rect_height(dst), diff);
>
> - src->y1 = clamp_t(int64_t, src->y2 - new_src_h, INT_MIN, INT_MAX);
> + src->y1 = src->y2 - new_src_h;
> dst->y1 = clip->y1;
> }
> diff = dst->x2 - clip->x2;
> @@ -105,7 +105,7 @@ bool drm_rect_clip_scaled(struct drm_rect *src, struct drm_rect *dst,
> u32 new_src_w = clip_scaled(drm_rect_width(src),
> drm_rect_width(dst), diff);
>
> - src->x2 = clamp_t(int64_t, src->x1 + new_src_w, INT_MIN, INT_MAX);
> + src->x2 = src->x1 + new_src_w;
> dst->x2 = clip->x2;
> }
> diff = dst->y2 - clip->y2;
> @@ -113,7 +113,7 @@ bool drm_rect_clip_scaled(struct drm_rect *src, struct drm_rect *dst,
> u32 new_src_h = clip_scaled(drm_rect_height(src),
> drm_rect_height(dst), diff);
>
> - src->y2 = clamp_t(int64_t, src->y1 + new_src_h, INT_MIN, INT_MAX);
> + src->y2 = src->y1 + new_src_h;
> dst->y2 = clip->y2;
> }
>
> --
> 2.15.0
>
> _______________________________________________
> dri-devel mailing list
> [email protected]
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

--
Ville Syrj?l?
Intel

2019-11-20 17:36:26

by Ville Syrjälä

Subject: Re: [PATCH] drm/rect: remove useless call to clamp_t

On Wed, Nov 20, 2019 at 05:22:34PM +0200, Ville Syrj?l? wrote:
> On Tue, Nov 19, 2019 at 02:34:35PM +0100, Benjamin Gaignard wrote:
> > Clamping a value between INT_MIN and INT_MAX always return the value itself
> > and generate warnings when compiling with W=1.
> >
> > Signed-off-by: Benjamin Gaignard <[email protected]>
> > ---
> > drivers/gpu/drm/drm_rect.c | 8 ++++----
> > 1 file changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_rect.c b/drivers/gpu/drm/drm_rect.c
> > index b8363aaa9032..681f1fd09357 100644
> > --- a/drivers/gpu/drm/drm_rect.c
> > +++ b/drivers/gpu/drm/drm_rect.c
> > @@ -89,7 +89,7 @@ bool drm_rect_clip_scaled(struct drm_rect *src, struct drm_rect *dst,
> > u32 new_src_w = clip_scaled(drm_rect_width(src),
> > drm_rect_width(dst), diff);
>
> Hmm. I think we borked this a bit when introducing clip_scaled().
> 'diff' can exceed dst width here so clip_scaled() should be able to
> return a negative value.
>
> Probably we should make this more consistent and do something like:
> diff = clip->x1 - dst->x1;
> if (diff > 0) {
> - u32 new_src_w = clip_scaled(drm_rect_width(src),
> - drm_rect_width(dst), diff);
> + int dst_w, new_src_w;
>
> - src->x1 = clamp_t(int64_t, src->x2 - new_src_w, INT_MIN, INT_MAX);
> - dst->x1 = clip->x1;
> + dst_w = drm_rect_width(dst);
> + diff = min(diff, dst_w);
> + new_src_w = clip_scaled(drm_rect_width(src), dst_w, diff);
> +
> + src->x1 = src->x2 - new_src_w;
> + dst->x1 += diff;
> }
>
> etc.

I tried to refine that a bit more and sent it out as two patches.

>
> >
> > - src->x1 = clamp_t(int64_t, src->x2 - new_src_w, INT_MIN, INT_MAX);
> > + src->x1 = src->x2 - new_src_w;
> > dst->x1 = clip->x1;
> > }
> > diff = clip->y1 - dst->y1;
> > @@ -97,7 +97,7 @@ bool drm_rect_clip_scaled(struct drm_rect *src, struct drm_rect *dst,
> > u32 new_src_h = clip_scaled(drm_rect_height(src),
> > drm_rect_height(dst), diff);
> >
> > - src->y1 = clamp_t(int64_t, src->y2 - new_src_h, INT_MIN, INT_MAX);
> > + src->y1 = src->y2 - new_src_h;
> > dst->y1 = clip->y1;
> > }
> > diff = dst->x2 - clip->x2;
> > @@ -105,7 +105,7 @@ bool drm_rect_clip_scaled(struct drm_rect *src, struct drm_rect *dst,
> > u32 new_src_w = clip_scaled(drm_rect_width(src),
> > drm_rect_width(dst), diff);
> >
> > - src->x2 = clamp_t(int64_t, src->x1 + new_src_w, INT_MIN, INT_MAX);
> > + src->x2 = src->x1 + new_src_w;
> > dst->x2 = clip->x2;
> > }
> > diff = dst->y2 - clip->y2;
> > @@ -113,7 +113,7 @@ bool drm_rect_clip_scaled(struct drm_rect *src, struct drm_rect *dst,
> > u32 new_src_h = clip_scaled(drm_rect_height(src),
> > drm_rect_height(dst), diff);
> >
> > - src->y2 = clamp_t(int64_t, src->y1 + new_src_h, INT_MIN, INT_MAX);
> > + src->y2 = src->y1 + new_src_h;
> > dst->y2 = clip->y2;
> > }
> >
> > --
> > 2.15.0
> >
> > _______________________________________________
> > dri-devel mailing list
> > [email protected]
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
>
> --
> Ville Syrj?l?
> Intel

--
Ville Syrj?l?
Intel