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

[Alexandru-Cosmin Gheorghe]

On Tue, Aug 28, 2018 at 04:48:45PM +0100, Brian Starkey wrote:
> 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 at arm.com>
> >---
> >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.

It's needed as an argument for
drm_atomic_replace_property_blob_from_id, and the prototype of the
function makes sense to me.

> 
> 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
> >

-- 
Cheers,
Alex G