Re: [Intel-gfx] [PATCH v3 09/11] drm/i915: Add a platform independent way to check for CCS AUX planes

[Imre Deak <imre.deak@intel.com>]

On Tue, Oct 19, 2021 at 11:38:33AM +0300, Imre Deak wrote:
> On Tue, Oct 19, 2021 at 11:02:45AM +0300, Jani Nikula wrote:
> > 
> > From patch 1:
> > 
> > static bool check_modifier_display_ver(const struct intel_modifier_desc *md,
> > 				       u8 display_ver)
> > {
> > 	return display_ver >= md->display_ver.from &&
> > 	       display_ver <= md->display_ver.until;
> > }
> > 
> > On Fri, 15 Oct 2021, Imre Deak <imre.deak@intel.com> wrote:
> > > +static bool check_modifier_display_ver_range(const struct intel_modifier_desc *md,
> > > +					     u8 display_ver_from, u8 display_ver_until)
> > > +{
> > > +	return check_modifier_display_ver(md, display_ver_from) &&
> > > +	       check_modifier_display_ver(md, display_ver_until);
> > > +}
> > > +
> > 
> > ...
> > 
> > > +/**
> > > + * intel_fb_is_gen12_ccs_aux_plane: Check if a framebuffer color plane is a GEN12 CCS AUX plane
> > > + * @fb: Framebuffer
> > > + * @color_plane: color plane index to check
> > > + *
> > > + * Returns:
> > > + * Returns %true if @fb's color plane at index @color_plane is a GEN12 CCS AUX plane.
> > > + */
> > > +static bool intel_fb_is_gen12_ccs_aux_plane(const struct drm_framebuffer *fb, int color_plane)
> > >  {
> > > -	return is_gen12_ccs_modifier(fb->modifier) && is_ccs_plane(fb, plane);
> > > +	const struct intel_modifier_desc *md = lookup_modifier(fb->modifier);
> > > +
> > > +	return check_modifier_display_ver_range(md, 12, 13) &&
> > > +	       ccs_aux_plane_mask(md, fb->format) & BIT(color_plane);
> > >  }
> > 
> > check_modifier_display_ver_range(md, 12, 13)
> > 
> > ==>
> > 
> > check_modifier_display_ver(md, 12) &&
> > check_modifier_display_ver(md, 13)
> > 
> > ==>
> > 
> > 12 >= md->display_ver.from &&
> > 12 <= md->display_ver.until &&
> > 13 >= md->display_ver.from &&
> > 13 <= md->display_ver.until
> > 
> > ==>
> > 
> > Always false.
> 
> If md->display_ver.from=12, md->display_ver.until=13
> 
> 12 >= 12 &&
> 12 <= 13 &&
> 13 >= 12 &&
> 13 <= 13
> 
> not false.
> 
> But yes, check_modifier_display_ver_range() is bogus for the
> md->display_ver.from == md->display_ver.until case, and should be
> 
> md->display_ver.from >= display_ver_from &&
> md->display_ver.until <= disaply_ver_until

arg the above is still bogus and should be:

 check_modifier_display_ver(md, display_ver_from) ||
 check_modifier_display_ver(md, display_ver_until);

> Thanks for catching this, will fix it.
> 
> > BR,
> > Jani.
> > 
> > 
> > -- 
> > Jani Nikula, Intel Open Source Graphics Center