On Mon, Jan 24, 2022 at 05:18:07PM -0500, Alex Deucher wrote:
> On Mon, Jan 24, 2022 at 5:16 PM Daniel Vetter <daniel.vetter@xxxxxxxx> wrote:
> >
> > Also add notes that for atomic drivers it's really somewhere else and
> > no longer in struct drm_crtc.
> >
> > Maybe we should put a bigger warning here that this is confusing,
> > since the pixel format is a plane property, but the GAMMA_LUT property
> > is on the crtc. But I think we can fix this if/when someone finds a
> > need for a per-plane CLUT, since I'm not sure such hw even exists. I'm
> > also not sure whether even hardware with a CLUT and a full color
> > correction pipeline with degamm/cgm/gamma exists.
> >
> > Motivated by comments from Geert that we have a gap here.
> >
> > v2: More names for color luts (Laurent).
> >
> > Cc: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> > Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> > Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> > Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> > Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
> > Cc: Maxime Ripard <mripard@xxxxxxxxxx>
> > Cc: Thomas Zimmermann <tzimmermann@xxxxxxx>
> > Cc: David Airlie <airlied@xxxxxxxx>
> > Cc: Daniel Vetter <daniel@xxxxxxxx>
> > Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
>
> Reviewed-by: Alex Deucher <alexander.deucher@xxxxxxx>
Thanks for taking a look, pushed to drm-misc-next.
-Daniel
>
> > ---
> > drivers/gpu/drm/drm_color_mgmt.c | 4 ++++
> > include/drm/drm_crtc.h | 10 ++++++++++
> > 2 files changed, 14 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/drm_color_mgmt.c b/drivers/gpu/drm/drm_color_mgmt.c
> > index bb14f488c8f6..9079fbe21d2f 100644
> > --- a/drivers/gpu/drm/drm_color_mgmt.c
> > +++ b/drivers/gpu/drm/drm_color_mgmt.c
> > @@ -82,6 +82,10 @@
> > * driver boot-up state too. Drivers can access this blob through
> > * &drm_crtc_state.gamma_lut.
> > *
> > + * Note that for mostly historical reasons stemming from Xorg heritage,
> > + * this is also used to store the color map (also sometimes color lut, CLUT
> > + * or color palette) for indexed formats like DRM_FORMAT_C8.
> > + *
> > * “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).
> > diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> > index 4d01b4d89775..a70baea0636c 100644
> > --- a/include/drm/drm_crtc.h
> > +++ b/include/drm/drm_crtc.h
> > @@ -285,6 +285,10 @@ struct drm_crtc_state {
> > * Lookup table for converting pixel data after the color conversion
> > * matrix @ctm. See drm_crtc_enable_color_mgmt(). The blob (if not
> > * NULL) is an array of &struct drm_color_lut.
> > + *
> > + * Note that for mostly historical reasons stemming from Xorg heritage,
> > + * this is also used to store the color map (also sometimes color lut,
> > + * CLUT or color palette) for indexed formats like DRM_FORMAT_C8.
> > */
> > struct drm_property_blob *gamma_lut;
> >
> > @@ -1075,12 +1079,18 @@ struct drm_crtc {
> > /**
> > * @gamma_size: Size of legacy gamma ramp reported to userspace. Set up
> > * by calling drm_mode_crtc_set_gamma_size().
> > + *
> > + * Note that atomic drivers need to instead use
> > + * &drm_crtc_state.gamma_lut. See drm_crtc_enable_color_mgmt().
> > */
> > uint32_t gamma_size;
> >
> > /**
> > * @gamma_store: Gamma ramp values used by the legacy SETGAMMA and
> > * GETGAMMA IOCTls. Set up by calling drm_mode_crtc_set_gamma_size().
> > + *
> > + * Note that atomic drivers need to instead use
> > + * &drm_crtc_state.gamma_lut. See drm_crtc_enable_color_mgmt().
> > */
> > uint16_t *gamma_store;
> >
> > --
> > 2.33.0
> >
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
