Hi Tomi,
Thank you for the patch.
On Tue, Nov 03, 2020 at 10:03:06AM +0200, Tomi Valkeinen wrote:
> We currently have drm_atomic_helper_legacy_gamma_set() helper which can
> be used to handle legacy gamma-set ioctl.
> drm_atomic_helper_legacy_gamma_set() sets GAMMA_LUT, and clears
> CTM and DEGAMMA_LUT. This works fine on HW where we have either:
>
> degamma -> ctm -> gamma -> out
>
> or
>
> ctm -> gamma -> out
>
> However, if the HW has gamma table before ctm, the atomic property
> should be DEGAMMA_LUT, and thus we have:
>
> degamma -> ctm -> out
>
> This is fine for userspace which sets gamma table using the properties,
> as the userspace can check for the existence of gamma & degamma, but the
> legacy gamma-set ioctl does not work.
>
> This patch adds a new helper, drm_atomic_helper_legacy_degamma_set(),
> which can be used instead of drm_atomic_helper_legacy_gamma_set() when
> the DEGAMMA_LUT is the underlying property that needs to be set.
>
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
> Reviewed-by: Pekka Paalanen <pekka.paalanen@xxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/drm_atomic_helper.c | 81 ++++++++++++++++++++++-------
> include/drm/drm_atomic_helper.h | 4 ++
> 2 files changed, 65 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> index ddd0e3239150..23cbed541dc7 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -3499,24 +3499,11 @@ int drm_atomic_helper_page_flip_target(struct drm_crtc *crtc,
> }
> EXPORT_SYMBOL(drm_atomic_helper_page_flip_target);
>
> -/**
> - * drm_atomic_helper_legacy_gamma_set - set the legacy gamma correction table
> - * @crtc: CRTC object
> - * @red: red correction table
> - * @green: green correction table
> - * @blue: green correction table
> - * @size: size of the tables
> - * @ctx: lock acquire context
> - *
> - * Implements support for legacy gamma correction table for drivers
> - * that support color management through the DEGAMMA_LUT/GAMMA_LUT
> - * properties. See drm_crtc_enable_color_mgmt() and the containing chapter for
> - * how the atomic color management and gamma tables work.
> - */
> -int drm_atomic_helper_legacy_gamma_set(struct drm_crtc *crtc,
> - u16 *red, u16 *green, u16 *blue,
> - uint32_t size,
> - struct drm_modeset_acquire_ctx *ctx)
> +static int legacy_gamma_degamma_set(struct drm_crtc *crtc,
> + u16 *red, u16 *green, u16 *blue,
> + uint32_t size,
> + struct drm_modeset_acquire_ctx *ctx,
> + bool use_degamma)
> {
> struct drm_device *dev = crtc->dev;
> struct drm_atomic_state *state;
> @@ -3555,9 +3542,11 @@ int drm_atomic_helper_legacy_gamma_set(struct drm_crtc *crtc,
> }
>
> /* Reset DEGAMMA_LUT and CTM properties. */
> - replaced = drm_property_replace_blob(&crtc_state->degamma_lut, NULL);
> + replaced = drm_property_replace_blob(&crtc_state->degamma_lut,
> + use_degamma ? blob : NULL);
> replaced |= drm_property_replace_blob(&crtc_state->ctm, NULL);
> - replaced |= drm_property_replace_blob(&crtc_state->gamma_lut, blob);
> + replaced |= drm_property_replace_blob(&crtc_state->gamma_lut,
> + use_degamma ? NULL : blob);
> crtc_state->color_mgmt_changed |= replaced;
>
> ret = drm_atomic_commit(state);
> @@ -3567,8 +3556,60 @@ int drm_atomic_helper_legacy_gamma_set(struct drm_crtc *crtc,
> drm_property_blob_put(blob);
> return ret;
> }
> +
> +/**
> + * drm_atomic_helper_legacy_gamma_set - set the legacy gamma correction table using gamma_lut
> + * @crtc: CRTC object
> + * @red: red correction table
> + * @green: green correction table
> + * @blue: green correction table
> + * @size: size of the tables
> + * @ctx: lock acquire context
> + *
> + * Implements support for legacy gamma correction table for drivers
> + * that support color management through the DEGAMMA_LUT/GAMMA_LUT
> + * properties. See drm_crtc_enable_color_mgmt() and the containing chapter for
> + * how the atomic color management and gamma tables work.
> + *
> + * This function uses GAMMA_LUT property for the gamma table. This function
s/uses/uses the/
s/This function$/It/
Same below.
> + * can be used when the driver exposes either only GAMMA_LUT or both GAMMA_LUT
> + * and DEGAMMA_LUT.
> + */
> +int drm_atomic_helper_legacy_gamma_set(struct drm_crtc *crtc,
> + u16 *red, u16 *green, u16 *blue,
> + uint32_t size,
> + struct drm_modeset_acquire_ctx *ctx)
> +{
> + return legacy_gamma_degamma_set(crtc, red, green, blue, size, ctx, false);
> +}
I wonder, would it make sense to make this automatic by setting the
degamma LUT when only the DEGAMMA_LUT property exists, and the gamma LUT
otherwise ? Are there use cases for drm_atomic_helper_legacy_degamma_set
for drivers that support both gamma and degamma ?
> EXPORT_SYMBOL(drm_atomic_helper_legacy_gamma_set);
>
> +/**
> + * drm_atomic_helper_legacy_degamma_set - set the legacy gamma correction table using degamma_lut
> + * @crtc: CRTC object
> + * @red: red correction table
> + * @green: green correction table
> + * @blue: green correction table
> + * @size: size of the tables
> + * @ctx: lock acquire context
> + *
> + * Implements support for legacy gamma correction table for drivers
> + * that support color management through the DEGAMMA_LUT/GAMMA_LUT
> + * properties. See drm_crtc_enable_color_mgmt() and the containing chapter for
> + * how the atomic color management and gamma tables work.
> + *
> + * This function uses DEGAMMA_LUT property for the gamma table. This function
> + * can be used when the driver exposes only DEGAMNMA_LUT.
> + */
> +int drm_atomic_helper_legacy_degamma_set(struct drm_crtc *crtc,
> + u16 *red, u16 *green, u16 *blue,
> + uint32_t size,
> + struct drm_modeset_acquire_ctx *ctx)
> +{
> + return legacy_gamma_degamma_set(crtc, red, green, blue, size, ctx, true);
> +}
> +EXPORT_SYMBOL(drm_atomic_helper_legacy_degamma_set);
> +
> /**
> * drm_atomic_helper_bridge_propagate_bus_fmt() - Propagate output format to
> * the input end of a bridge
> diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h
> index 85df04c8e62f..561c78680388 100644
> --- a/include/drm/drm_atomic_helper.h
> +++ b/include/drm/drm_atomic_helper.h
> @@ -151,6 +151,10 @@ int drm_atomic_helper_legacy_gamma_set(struct drm_crtc *crtc,
> u16 *red, u16 *green, u16 *blue,
> uint32_t size,
> struct drm_modeset_acquire_ctx *ctx);
> +int drm_atomic_helper_legacy_degamma_set(struct drm_crtc *crtc,
> + u16 *red, u16 *green, u16 *blue,
> + uint32_t size,
> + struct drm_modeset_acquire_ctx *ctx);
>
> /**
> * drm_atomic_crtc_for_each_plane - iterate over planes currently attached to CRTC
--
Regards,
Laurent Pinchart
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