Re: [PATCH] drm/i915/bxt: Fix uninitialized variables in intel_check_sprite_plane

["Maiti, Nabendu Bikash" <nabendu.bikash.maiti@xxxxxxxxx>]

On 11/18/2015 6:22 PM, Ville Syrjälä wrote:
> On Wed, Nov 18, 2015 at 12:19:06PM +0000, Chris Wilson wrote:
> > On Wed, Nov 18, 2015 at 05:43:52PM +0530, Nabendu Maiti wrote:
> > > Uninitialized variables (width, Height) in intel_check_sprite_plane
> > > leads to compilererror in O1 level. Initialize all declared variables
> > > to fix this issue.
> > >
> > > Signed-off-by: Nabendu Maiti <nabendu.bikash.maiti@xxxxxxxxx>
> > Or perhaps:
> >
> > diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c
> > index 2b96f336589e..8d7b4eb5b5b9 100644
> > --- a/drivers/gpu/drm/i915/intel_sprite.c
> > +++ b/drivers/gpu/drm/i915/intel_sprite.c
> > @@ -747,7 +747,6 @@ intel_check_sprite_plane(struct drm_plane *plane,
> >          struct drm_framebuffer *fb = state->base.fb;
> >          int crtc_x, crtc_y;
> >          unsigned int crtc_w, crtc_h;
> > -       uint32_t src_x, src_y, src_w, src_h;
> >          struct drm_rect *src = &state->src;
> >          struct drm_rect *dst = &state->dst;
> >          const struct drm_rect *clip = &state->clip;
> > @@ -813,6 +812,8 @@ intel_check_sprite_plane(struct drm_plane *plane,
> >          crtc_h = drm_rect_height(dst);
> >   
> >          if (state->visible) {
> > +               u32 src_x, src_y, src_w, src_h;
> > +
> >                  /* check again in case clipping clamped the results */
> >                  hscale = drm_rect_calc_hscale(src, dst, min_scale, max_scale);
> >                  if (hscale < 0) {
> > @@ -871,10 +872,9 @@ intel_check_sprite_plane(struct drm_plane *plane,
> >                          if (crtc_w == 0)
> >                                  state->visible = false;
> >                  }
> > -       }
> >   
> >                  /* Check size restrictions when scaling */
> > -       if (state->visible && (src_w != crtc_w || src_h != crtc_h)) {
> > +               if (src_w != crtc_w || src_h != crtc_h) {
> That would change what it does.
yes, checked the code where inside each if condition loop we may be 
changing the state->visible var itself. Next condition check it may be 
false too.

The place giving compiler error
                src->x1 = src_x << 16;
                src->x2 = (src_x + src_w) << 16;
                src->y1 = src_y << 16;
                src->y2 = (src_y + src_h) << 16;

Then just one line change of initializing the variables is better?

> >                          unsigned int width_bytes;
> >   
> >                          WARN_ON(!can_scale);
> > @@ -898,7 +898,6 @@ intel_check_sprite_plane(struct drm_plane *plane,
> >                          }
> >                  }
> >   
> > -       if (state->visible) {
> >                  src->x1 = src_x << 16;
> >                  src->x2 = (src_x + src_w) << 16;
> >                  src->y1 = src_y << 16;
> >
> > And make both the compiler and reader happier
> > -Chris
> >
> > --
> > Chris Wilson, Intel Open Source Technology Centre
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx

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