[PATCH] drm/color: document NULL values and default settings better

[Daniel Vetter]

On Tue, Nov 15, 2016 at 03:39:01PM +0000, Lionel Landwerlin wrote:
> Sorry for missing this.
> 
> Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>

np and thanks a lot for reviewing.
-Daniel

> 
> On 26/09/16 10:04, Daniel Vetter wrote:
> > Brought up in a discussion for enabling gamma on fsl-dcu.
> > 
> > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > Cc: Meng Yi <meng.yi at nxp.com>
> > Cc: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
> > Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> > ---
> >   drivers/gpu/drm/drm_color_mgmt.c | 12 ++++++++++++
> >   1 file changed, 12 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/drm_color_mgmt.c 
> > b/drivers/gpu/drm/drm_color_mgmt.c
> > index d28ffdd2b929..6543ebde501a 100644
> > --- a/drivers/gpu/drm/drm_color_mgmt.c
> > +++ b/drivers/gpu/drm/drm_color_mgmt.c
> > @@ -41,6 +41,10 @@
> >    *        nor use all the elements of the LUT (for example the hardware 
> > might
> >    *        choose to interpolate between LUT[0] and LUT[4]).
> >    *
> > + * Setting this to NULL (blob property value set to 0) means a
> > + * linear/pass-thru gamma table should be used. This is generally the
> > + * driver boot-up state too.
> > + *
> >    * “DEGAMMA_LUT_SIZE”:
> >    *        Unsinged range property to give the size of the lookup table to 
> > be set
> >    *        on the DEGAMMA_LUT property (the size depends on the underlying
> > @@ -54,6 +58,10 @@
> >    *        lookup through the gamma LUT. The data is interpreted as a 
> > struct
> >    *        &drm_color_ctm.
> >    *
> > + * Setting this to NULL (blob property value set to 0) means a
> > + * unit/pass-thru matrix should be used. This is generally the driver
> > + * boot-up state too.
> > + *
> >    * “GAMMA_LUT”:
> >    *        Blob property to set the gamma lookup table (LUT) mapping pixel 
> > data
> >    *        after the transformation matrix to data sent to the connector. 
> > The
> > @@ -62,6 +70,10 @@
> >    *        nor use all the elements of the LUT (for example the hardware 
> > might
> >    *        choose to interpolate between LUT[0] and LUT[4]).
> >    *
> > + * Setting this to NULL (blob property value set to 0) means a
> > + * linear/pass-thru gamma table should be used. This is generally the
> > + * driver boot-up state too.
> > + *
> >    * “GAMMA_LUT_SIZE”:
> >    *        Unsigned range property to give the size of the lookup table to 
> > be set
> >    *        on the GAMMA_LUT property (the size depends on the underlying 
> > hardware).
> 
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch