[PATCH] drm/atomic-helpers: Properly avoid full modeset dance

Daniel Vetter
2015-03-26T21:46:24Z

Legacy setCrtc has a nice fastpath for just updating the frontbuffer
when the output routing doesn't change. Which I of course tried to
keep working, except that I fumbled the job: The helpers correctly
compute ->mode_changed, CRTC updates get correctly skipped but
connector functions are called unconditionally.

Fix this.

Reported-and-Tested-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
drivers/gpu/drm/drm_atomic_helper.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index d9ed9a54fd1e..6e377d954538 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -587,7 +587,8 @@ disable_outputs(struct drm_device *dev, struct drm_atomic_state *old_state)

old_crtc_state = old_state->crtc_states[drm_crtc_index(old_conn_state->crtc)];

- if (!old_crtc_state->active)
+ if (!old_crtc_state->active ||
+ !needs_modeset(connector->state->crtc->state))
continue;

encoder = old_conn_state->best_encoder;
@@ -847,7 +848,8 @@ void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev,
if (!connector || !connector->state->best_encoder)
continue;

- if (!connector->state->crtc->state->active)
+ if (!connector->state->crtc->state->active ||
+ !needs_modeset(connector->state->crtc->state))
continue;

encoder = connector->state->best_encoder;
--
2.1.4