Re: [PATCH v2] drm: Fix crtc color management when doing suspend/resume

[Brian Starkey <brian.starkey@xxxxxxx>]

Hi Alex,

On Tue, Aug 28, 2018 at 04:33:20PM +0100, Alexandru Gheorghe wrote:
> When doing suspend/resume drivers usually use the
> drm_atomic_helper_suspend/drm_atomic_helper_resume pair for saving the
> state and then re-comitting it.
>
> The problem is that drm_crtc_state has a bool field called
> color_mgmt_changed, which mali-dp and other drivers uses it to detect
> if coefficients need to be reprogrammed, but that never happens
> because the saved state has color_mgmt_changed set to 0.
>
> Fix that by setting color_mgmt_changed to true in
> drm_atomic_helper_check_modeset when at least one of gamma_lut,
> degamma_lut, ctm is different between the new and the old crtc state.
>
> Also, this makes unnecessary the setting of color_mgmt_changed in
> places where gamma_lut/degamma_lut/ctm are set in the new crtc_state.
>
> Changes since v2:
>  - Instead of setting color_mgmt_changed in commit_duplicated_set
>    just set it in check_modeset and clean up other place where it was
>    set, suggested by Maarten Lankhorst.
>
> Signed-off-by: Alexandru Gheorghe <alexandru-cosmin.gheorghe@xxxxxxx>
> ---
> drivers/gpu/drm/drm_atomic.c        | 12 +++---------
> drivers/gpu/drm/drm_atomic_helper.c |  8 +++++++-
> drivers/gpu/drm/drm_fb_helper.c     |  1 -
> 3 files changed, 10 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> index d0478abc01bd..9bcada3c299e 100644
> --- a/drivers/gpu/drm/drm_atomic.c
> +++ b/drivers/gpu/drm/drm_atomic.c
> @@ -554,29 +554,23 @@ int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
> 		drm_property_blob_put(mode);
> 		return ret;
> 	} else if (property == config->degamma_lut_property) {
> -		ret = drm_atomic_replace_property_blob_from_id(dev,
> +		return drm_atomic_replace_property_blob_from_id(dev,
> 					&state->degamma_lut,
> 					val,
> 					-1, sizeof(struct drm_color_lut),
> 					&replaced);
> -		state->color_mgmt_changed |= replaced;
> -		return ret;
> 	} else if (property == config->ctm_property) {
> -		ret = drm_atomic_replace_property_blob_from_id(dev,
> +		return drm_atomic_replace_property_blob_from_id(dev,
> 					&state->ctm,
> 					val,
> 					sizeof(struct drm_color_ctm), -1,
> 					&replaced);
> -		state->color_mgmt_changed |= replaced;
> -		return ret;
> 	} else if (property == config->gamma_lut_property) {
> -		ret = drm_atomic_replace_property_blob_from_id(dev,
> +		return drm_atomic_replace_property_blob_from_id(dev,
> 					&state->gamma_lut,
> 					val,
> 					-1, sizeof(struct drm_color_lut),
> 					&replaced);
> -		state->color_mgmt_changed |= replaced;
> -		return ret;

Looks like 'replaced' is now unused, so you can remove it.

Cheers,
-Brian

> 	} else if (property == config->prop_out_fence_ptr) {
> 		s32 __user *fence_ptr = u64_to_user_ptr(val);
>
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> index 2c23a48482da..fe22e1ad468a 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -611,6 +611,13 @@ drm_atomic_helper_check_modeset(struct drm_device *dev,
>
> 			return -EINVAL;
> 		}
> +		if (new_crtc_state->degamma_lut != old_crtc_state->degamma_lut ||
> +		    new_crtc_state->ctm != old_crtc_state->ctm ||
> +		    new_crtc_state->gamma_lut != old_crtc_state->gamma_lut) {
> +			DRM_DEBUG_ATOMIC("[CRTC:%d:%s] color management changed\n",
> +					 crtc->base.id, crtc->name);
> +			new_crtc_state->color_mgmt_changed = true;
> +		}
> 	}
>
> 	ret = handle_conflicting_encoders(state, false);
> @@ -3947,7 +3954,6 @@ int drm_atomic_helper_legacy_gamma_set(struct drm_crtc *crtc,
> 	replaced  = drm_property_replace_blob(&crtc_state->degamma_lut, NULL);
> 	replaced |= drm_property_replace_blob(&crtc_state->ctm, NULL);
> 	replaced |= drm_property_replace_blob(&crtc_state->gamma_lut, blob);
> -	crtc_state->color_mgmt_changed |= replaced;
>
> 	ret = drm_atomic_commit(state);
>
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index 4b0dd20bccb8..8541e95a5410 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -1442,7 +1442,6 @@ static int setcmap_atomic(struct fb_cmap *cmap, struct fb_info *info)
> 		replaced |= drm_property_replace_blob(&crtc_state->ctm, NULL);
> 		replaced |= drm_property_replace_blob(&crtc_state->gamma_lut,
> 						      gamma_lut);
> -		crtc_state->color_mgmt_changed |= replaced;
> 	}
>
> 	ret = drm_atomic_commit(state);
> --
> 2.18.0
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