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Message-Id: <20241222-drm-dirty-modeset-v1-2-0e76a53eceb9@linaro.org>
Date: Sun, 22 Dec 2024 07:00:42 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
Rob Clark <robdclark@...il.com>, Abhinav Kumar <quic_abhinavk@...cinc.com>,
Sean Paul <sean@...rly.run>, Marijn Suijten <marijn.suijten@...ainline.org>,
Chandan Uddaraju <chandanu@...eaurora.org>,
Jeykumar Sankaran <jsanka@...eaurora.org>,
Jordan Crouse <jordan@...micpenguin.net>,
Sravanthi Kollukuduru <skolluku@...eaurora.org>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
Archit Taneja <architt@...eaurora.org>,
Rajesh Yadav <ryadav@...eaurora.org>, linux-arm-msm@...r.kernel.org,
freedreno@...ts.freedesktop.org, Simona Vetter <simona.vetter@...ll.ch>
Subject: [PATCH 2/6] drm/atomic: prepare to check that drivers follow
restrictions for needs_modeset
Some drivers might fail to follow the restrictions documented for
drm_atomic_helper_check_modesets(). In order to catch such an issues,
add the drm_atomic_state->dirty_needs_modeset field and check it in
drm_atomic_check_only(). Make sure that neither of atomic_check()
callbacks can set that field without calling
drm_atomic_helper_check_modesets() again.
Suggested-by: Simona Vetter <simona.vetter@...ll.ch>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
---
drivers/gpu/drm/drm_atomic.c | 3 ++
drivers/gpu/drm/drm_atomic_helper.c | 77 +++++++++++++++++++++++++++++++++----
include/drm/drm_atomic.h | 10 +++++
3 files changed, 82 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 9ea2611770f43ce7ccba410406d5f2c528aab022..202e4e64bd31921d0a4d4b86605b501311e14c33 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -1449,6 +1449,9 @@ int drm_atomic_check_only(struct drm_atomic_state *state)
}
}
+ WARN_RATELIMIT(state->dirty_needs_modeset,
+ "Driver changed needs_modeset under drm_atomic_helper_check_modeset()");
+
if (!state->allow_modeset) {
for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) {
if (drm_atomic_crtc_needs_modeset(new_crtc_state)) {
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index f26887c3fe8b194137200f9f2426653274c50fda..2c62840416f4b807d6a880b5c30ae024a16af528 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -433,6 +433,7 @@ mode_fixup(struct drm_atomic_state *state)
for_each_new_connector_in_state(state, connector, new_conn_state, i) {
const struct drm_encoder_helper_funcs *funcs;
+ bool old_needs_modeset = false;
struct drm_encoder *encoder;
struct drm_bridge *bridge;
@@ -451,6 +452,9 @@ mode_fixup(struct drm_atomic_state *state)
encoder = new_conn_state->best_encoder;
funcs = encoder->helper_private;
+ if (new_crtc_state)
+ old_needs_modeset = drm_atomic_crtc_needs_modeset(new_crtc_state);
+
bridge = drm_bridge_chain_get_first_bridge(encoder);
ret = drm_atomic_bridge_chain_check(bridge,
new_crtc_state,
@@ -479,6 +483,12 @@ mode_fixup(struct drm_atomic_state *state)
return -EINVAL;
}
}
+
+ if (new_crtc_state) {
+ bool new_needs_modeset = drm_atomic_crtc_needs_modeset(new_crtc_state);
+
+ state->dirty_needs_modeset |= (new_needs_modeset != old_needs_modeset);
+ }
}
for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) {
@@ -574,6 +584,36 @@ mode_valid(struct drm_atomic_state *state)
return 0;
}
+static int
+connector_atomic_check(struct drm_atomic_state *state,
+ struct drm_connector *connector,
+ struct drm_connector_state *old_connector_state,
+ struct drm_connector_state *new_connector_state)
+{
+ const struct drm_connector_helper_funcs *funcs = connector->helper_private;
+ struct drm_crtc_state *new_crtc_state;
+ bool old_needs_modeset = false;
+ int ret;
+
+ if (new_connector_state->crtc)
+ new_crtc_state = drm_atomic_get_new_crtc_state(state, new_connector_state->crtc);
+ if (new_crtc_state)
+ old_needs_modeset = drm_atomic_crtc_needs_modeset(new_crtc_state);
+
+ if (funcs->atomic_check)
+ ret = funcs->atomic_check(connector, state);
+ else
+ ret = 0;
+
+ if (new_crtc_state) {
+ bool new_needs_modeset = drm_atomic_crtc_needs_modeset(new_crtc_state);
+
+ state->dirty_needs_modeset |= (new_needs_modeset != old_needs_modeset);
+ }
+
+ return ret;
+}
+
/**
* drm_atomic_helper_check_modeset - validate state object for modeset changes
* @dev: DRM device
@@ -628,6 +668,8 @@ drm_atomic_helper_check_modeset(struct drm_device *dev,
int i, ret;
unsigned int connectors_mask = 0, user_connectors_mask = 0;
+ state->dirty_needs_modeset = false;
+
for_each_oldnew_connector_in_state(state, connector, old_connector_state, new_connector_state, i)
user_connectors_mask |= BIT(i);
@@ -683,8 +725,6 @@ drm_atomic_helper_check_modeset(struct drm_device *dev,
return ret;
for_each_oldnew_connector_in_state(state, connector, old_connector_state, new_connector_state, i) {
- const struct drm_connector_helper_funcs *funcs = connector->helper_private;
-
WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
/*
@@ -710,8 +750,8 @@ drm_atomic_helper_check_modeset(struct drm_device *dev,
new_crtc_state->connectors_changed = true;
}
- if (funcs->atomic_check)
- ret = funcs->atomic_check(connector, state);
+ ret = connector_atomic_check(state, connector,
+ old_connector_state, new_connector_state);
if (ret) {
drm_dbg_atomic(dev,
"[CONNECTOR:%d:%s] driver check failed\n",
@@ -752,13 +792,11 @@ drm_atomic_helper_check_modeset(struct drm_device *dev,
* has been called on them when a modeset is forced.
*/
for_each_oldnew_connector_in_state(state, connector, old_connector_state, new_connector_state, i) {
- const struct drm_connector_helper_funcs *funcs = connector->helper_private;
-
if (connectors_mask & BIT(i))
continue;
- if (funcs->atomic_check)
- ret = funcs->atomic_check(connector, state);
+ ret = connector_atomic_check(state, connector,
+ old_connector_state, new_connector_state);
if (ret) {
drm_dbg_atomic(dev,
"[CONNECTOR:%d:%s] driver check failed\n",
@@ -994,6 +1032,7 @@ drm_atomic_helper_check_planes(struct drm_device *dev,
for_each_oldnew_plane_in_state(state, plane, old_plane_state, new_plane_state, i) {
const struct drm_plane_helper_funcs *funcs;
+ bool old_needs_modeset = false;
WARN_ON(!drm_modeset_is_locked(&plane->mutex));
@@ -1006,6 +1045,12 @@ drm_atomic_helper_check_planes(struct drm_device *dev,
if (!funcs || !funcs->atomic_check)
continue;
+ if (new_plane_state->crtc)
+ new_crtc_state = drm_atomic_get_new_crtc_state(state,
+ new_plane_state->crtc);
+ if (new_crtc_state)
+ old_needs_modeset = drm_atomic_crtc_needs_modeset(new_crtc_state);
+
ret = funcs->atomic_check(plane, state);
if (ret) {
drm_dbg_atomic(plane->dev,
@@ -1013,16 +1058,26 @@ drm_atomic_helper_check_planes(struct drm_device *dev,
plane->base.id, plane->name);
return ret;
}
+
+ if (new_crtc_state) {
+ bool new_needs_modeset = drm_atomic_crtc_needs_modeset(new_crtc_state);
+
+ state->dirty_needs_modeset |= (new_needs_modeset != old_needs_modeset);
+ }
}
for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) {
const struct drm_crtc_helper_funcs *funcs;
+ bool old_needs_modeset = false;
funcs = crtc->helper_private;
if (!funcs || !funcs->atomic_check)
continue;
+ if (new_crtc_state)
+ old_needs_modeset = drm_atomic_crtc_needs_modeset(new_crtc_state);
+
ret = funcs->atomic_check(crtc, state);
if (ret) {
drm_dbg_atomic(crtc->dev,
@@ -1030,6 +1085,12 @@ drm_atomic_helper_check_planes(struct drm_device *dev,
crtc->base.id, crtc->name);
return ret;
}
+
+ if (new_crtc_state) {
+ bool new_needs_modeset = drm_atomic_crtc_needs_modeset(new_crtc_state);
+
+ state->dirty_needs_modeset |= (new_needs_modeset != old_needs_modeset);
+ }
}
return ret;
diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
index 31ca88deb10d262fb3a3f8e14d2afe24f8410cb1..7b0dbd3c8a3df340399a458aaf79263f0fdc24e5 100644
--- a/include/drm/drm_atomic.h
+++ b/include/drm/drm_atomic.h
@@ -408,6 +408,16 @@ struct drm_atomic_state {
*/
bool duplicated : 1;
+ /**
+ * @dirty_needs_modeset:
+ *
+ * Indicates whether the drm_atomic_crtc_needs_modeset() changed in an
+ * unexpected way. Usually this means that driver implements atomic
+ * helpers using drm_atomic_crtc_needs_modeset(), but mode_changed has
+ * toggled by one of its atomic_check() callbacks.
+ */
+ bool dirty_needs_modeset : 1;
+
/**
* @planes:
*
--
2.39.5
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