[PATCH v6 1/5] drm: Add function to convert rect in 16.16 fixed format to regular format

[Souza, Jose]

On Tue, 2020-12-15 at 12:52 +0000, Mun, Gwan-gyeong wrote:
> On Mon, 2020-12-14 at 09:49 -0800, José Roberto de Souza wrote:
> > Much more clear to read one function call than four lines doing this
> > conversion.
> > 
> > Cc: dri-devel at lists.freedesktop.org
> > Cc: Gwan-gyeong Mun <gwan-gyeong.mun at intel.com>
> > Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> > ---
> >  drivers/gpu/drm/drm_rect.c | 15 +++++++++++++++
> >  include/drm/drm_rect.h     |  2 ++
> >  2 files changed, 17 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/drm_rect.c b/drivers/gpu/drm/drm_rect.c
> > index 0460e874896e..24345704b353 100644
> > --- a/drivers/gpu/drm/drm_rect.c
> > +++ b/drivers/gpu/drm/drm_rect.c
> > @@ -373,3 +373,18 @@ void drm_rect_rotate_inv(struct drm_rect *r,
> >  	}
> >  }
> >  EXPORT_SYMBOL(drm_rect_rotate_inv);
> > +
> > +/**
> > + * drm_rect_convert_16_16_to_regular - Convert a rect in 16.16 fixed
> > point form
> > + * to regular form.
> > + * @in: rect in 16.16 fixed point form
> > + * @out: rect to be stored the converted value
> > + */
> > +void drm_rect_convert_16_16_to_regular(struct drm_rect *in, struct
> > drm_rect *out)
> > +{
> > +	out->x1 = in->x1 >> 16;
> > +	out->y1 = in->y1 >> 16;
> > +	out->x2 = in->x2 >> 16;
> > +	out->y2 = in->y2 >> 16;
> > +}
> > +EXPORT_SYMBOL(drm_rect_convert_16_16_to_regular);
> > diff --git a/include/drm/drm_rect.h b/include/drm/drm_rect.h
> > index e7f4d24cdd00..2ef8180416cd 100644
> > --- a/include/drm/drm_rect.h
> > +++ b/include/drm/drm_rect.h
> > @@ -223,5 +223,7 @@ void drm_rect_rotate(struct drm_rect *r,
> >  void drm_rect_rotate_inv(struct drm_rect *r,
> >  			 int width, int height,
> >  			 unsigned int rotation);
> > +void drm_rect_convert_16_16_to_regular(struct drm_rect *in,
> > +				       struct drm_rect *out);
> > 
> Hi,
> if it's purpose is just converting 16.16 fp to integer, how about you
> have function prototype like this?
> extern inline struct drm_rect
> drm_rect_convert_16_16_fp_to_integer(struct drm_rect in)

I prefer have a function call as this can be reused in several places, so the binaries size can decrease a bit.
Also pointers are better, compiler can decide to not inline the function above and it would need to allocate in stack 2 drm_rects for every call.

> 
> And if there are no use case on drm core or other drivers except i915
> display yet,
> before adding this function to drm core, how about you add this
> function code to i915 first?

There is plenty of users in other drivers, just not doing in this series.

> 
> Br,
> G.G.
> >  #endif