[PATCH 1/3] drm: Tune up error message during format->bpp/cpp conversion

[Imre Deak]

On Thu, 2016-05-12 at 16:10 +0300, Ville Syrjälä wrote:
> On Thu, May 12, 2016 at 04:00:38PM +0300, Imre Deak wrote:
> > Returning a 0 bpp/cpp value from these functions isn't ever valid.
> > In
> > many cases it can also lead to a div-by-zero possibly at some later
> > point in time, so make sure we catch such errors as soon as
> > possible via
> > louder error reporting.
> > 
> > CC: Dave Airlie <airlied at redhat.com>
> > Signed-off-by: Imre Deak <imre.deak at intel.com>
> > ---
> >  drivers/gpu/drm/drm_crtc.c | 10 +++++++---
> >  1 file changed, 7 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/drm_crtc.c
> > b/drivers/gpu/drm/drm_crtc.c
> > index 70f9c68..3a32606 100644
> > --- a/drivers/gpu/drm/drm_crtc.c
> > +++ b/drivers/gpu/drm/drm_crtc.c
> > @@ -5610,8 +5610,8 @@ void drm_fb_get_bpp_depth(uint32_t format,
> > unsigned int *depth,
> >            *bpp = 32;
> >            break;
> >    default:
> > -           DRM_DEBUG_KMS("unsupported pixel format %s\n",
> > -                         drm_get_format_name(format));
> > +           WARN(1, "unsupported pixel format %s\n",
> > +                drm_get_format_name(format));
> 
> NAK. This will happen every time drm_helper_mode_fill_fb_struct()
> is called with a non-RGB format.

Yep, missed that. So how about handling here those formats explicitly,
and emitting a warning only for truly unsupported formats?

> >            *depth = 0;
> >            *bpp = 0;
> >            break;
> > @@ -5666,8 +5666,12 @@ int drm_format_plane_cpp(uint32_t format,
> > int plane)
> >    unsigned int depth;
> >    int bpp;
> >  
> > -   if (plane >= drm_format_num_planes(format))
> > +   if (plane >= drm_format_num_planes(format)) {
> > +           WARN(1, "invalid plane %d for format %s\n",
> > +                plane, drm_get_format_name(format));
> > +
> 
> We have this check in many places. Should either convert all or none.

Ok, I can also change drm_format_plane_width()
and drm_format_plane_height(). Couldn't spot any other places.

> >            return 0;
> > +   }
> >  
> >    switch (format) {
> >    case DRM_FORMAT_YUYV:
> > -- 
> > 2.5.0
> > 
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>