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Message-ID: <20191120162544.GH1208@intel.com>
Date: Wed, 20 Nov 2019 18:25:44 +0200
From: Ville Syrjälä <ville.syrjala@...ux.intel.com>
To: Benjamin Gaignard <benjamin.gaignard@...com>
Cc: maarten.lankhorst@...ux.intel.com, mripard@...nel.org,
sean@...rly.run, airlied@...ux.ie, daniel@...ll.ch,
linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH] drm/rect: remove useless call to clamp_t
On Wed, Nov 20, 2019 at 05:22:34PM +0200, Ville Syrjälä 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 <benjamin.gaignard@...com>
> > ---
> > 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
> > dri-devel@...ts.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
>
> --
> Ville Syrjälä
> Intel
--
Ville Syrjälä
Intel
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