[PATCH 6.0 0192/1073] drm/atomic-helper: Dont allocate new plane state in CRTC check

Greg Kroah-Hartman
2022-12-28T15:18:21Z

From: Thomas Zimmermann <tzimmermann@suse.de>

[ Upstream commit dbbf933d365da1a76a540211bee3d57bde520194 ]

In drm_atomic_helper_check_crtc_state(), do not add a new plane state
to the global state if it does not exist already. Adding a new plane
state will result in overhead for the plane during the atomic-commit
step.

For the test in drm_atomic_helper_check_crtc_state() to succeed, it
is important that the CRTC has an enabled primary plane after the
commit. Simply testing the CRTC state's plane_mask for a primary plane
is sufficient.

Note that the helper still only tests for an attached primary plane.
Drivers have to ensure that the plane contains valid pixel information.

v5:
* fix commit description (Javier)
v3:
* test for a primary plane in plane_mask (Ville)
v2:
* remove unnecessary test for plane->crtc (Ville)
* inline drm_atomic_get_next_plane_state() (Ville)
* acquire plane lock before accessing plane->state (Ville)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Fixes: d6b9af1097fe ("drm/atomic-helper: Add helper drm_atomic_helper_check_crtc_state()")
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Jocelyn Falempe <jfalempe@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Link: https://patchwork.freedesktop.org/patch/msgid/20221007124338.24152-2-tzimmermann@suse.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/drm_atomic_helper.c | 10 +---------
1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 8bf41aa24068..6526d6ade04b 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -899,7 +899,6 @@ int drm_atomic_helper_check_crtc_state(struct drm_crtc_state *crtc_state,
bool can_disable_primary_planes)
{
struct drm_device *dev = crtc_state->crtc->dev;
- struct drm_atomic_state *state = crtc_state->state;

if (!crtc_state->enable)
return 0;
@@ -910,14 +909,7 @@ int drm_atomic_helper_check_crtc_state(struct drm_crtc_state *crtc_state,
struct drm_plane *plane;

drm_for_each_plane_mask(plane, dev, crtc_state->plane_mask) {
- struct drm_plane_state *plane_state;
-
- if (plane->type != DRM_PLANE_TYPE_PRIMARY)
- continue;
- plane_state = drm_atomic_get_plane_state(state, plane);
- if (IS_ERR(plane_state))
- return PTR_ERR(plane_state);
- if (plane_state->fb && plane_state->crtc) {
+ if (plane->type == DRM_PLANE_TYPE_PRIMARY) {
has_primary_plane = true;
break;
}
--
2.35.1