[PATCH v3 5/7] drm/atomic: Handle encoder assignment conflicts in a separate check, v3.

Maarten Lankhorst
2016-03-03T09:17:40Z

The current check doesn't handle the case where we don't steal an
encoder, but keep it on the current connector. If we repurpose
disable_conflicting_encoders to do the checking, we just have
to reject the ones that conflict.

Changes since v1:
- Return early with empty encoder_mask, drm_for_each_connector
requires connection_mutex held.
Changes since v2:
- Add comments for the loops.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Testcase: kms_setmode.invalid-clone-single-crtc-stealing
---
drivers/gpu/drm/drm_atomic_helper.c | 77 +++++++++++++++++++++----------------
1 file changed, 43 insertions(+), 34 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index db11c2f9b098..bb60148c5c8d 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -86,7 +86,8 @@ drm_atomic_helper_plane_changed(struct drm_atomic_state *state,
}
}

-static int disable_conflicting_connectors(struct drm_atomic_state *state)
+static int handle_conflicting_encoders(struct drm_atomic_state *state,
+ bool disable_conflicting_encoders)
{
struct drm_connector_state *conn_state;
struct drm_connector *connector;
@@ -94,6 +95,11 @@ static int disable_conflicting_connectors(struct drm_atomic_state *state)
unsigned encoder_mask = 0;
int i, ret;

+ /*
+ * First loop, find all newly assigned encoders from the connectors
+ * part of the state. If the same encoder is assigned to multiple
+ * connectors bail out.
+ */
for_each_connector_in_state(state, connector, conn_state, i) {
const struct drm_connector_helper_funcs *funcs = connector->helper_private;
struct drm_encoder *new_encoder;
@@ -106,10 +112,33 @@ static int disable_conflicting_connectors(struct drm_atomic_state *state)
else
new_encoder = funcs->best_encoder(connector);

- if (new_encoder)
+ if (new_encoder) {
+ if (encoder_mask & (1 << drm_encoder_index(new_encoder))) {
+ DRM_DEBUG_ATOMIC("[ENCODER:%d:%s] on [CONNECTOR:%d:%s] already assigned\n",
+ new_encoder->base.id, new_encoder->name,
+ connector->base.id, connector->name);
+
+ return -EINVAL;
+ }
+
encoder_mask |= 1 << drm_encoder_index(new_encoder);
+ }
}

+ if (!encoder_mask)
+ return 0;
+
+ /*
+ * Second loop, iterate over all connectors not part of the state.
+ *
+ * If a conflicting encoder is found and disable_conflicting_encoders
+ * is not set, an error is returned. Userspace can provide a solution
+ * through the atomic ioctl.
+ *
+ * If the flag is set conflicting connectors are removed from the crtc
+ * and the crtc is disabled if no encoder is left. This preserves
+ * compatibility with the legacy set_config behavior.
+ */
drm_for_each_connector(connector, state->dev) {
struct drm_crtc_state *crtc_state;

@@ -120,6 +149,15 @@ static int disable_conflicting_connectors(struct drm_atomic_state *state)
if (!encoder || !(encoder_mask & (1 << drm_encoder_index(encoder))))
continue;

+ if (!disable_conflicting_encoders) {
+ DRM_DEBUG_ATOMIC("[ENCODER:%d:%s] in use on [CRTC:%d:%s] by [CONNECTOR:%d:%s]\n",
+ encoder->base.id, encoder->name,
+ connector->state->crtc->base.id,
+ connector->state->crtc->name,
+ connector->base.id, connector->name);
+ return -EINVAL;
+ }
+
conn_state = drm_atomic_get_connector_state(state, connector);
if (IS_ERR(conn_state))
return PTR_ERR(conn_state);
@@ -148,26 +186,6 @@ static int disable_conflicting_connectors(struct drm_atomic_state *state)
return 0;
}

-static bool
-check_pending_encoder_assignment(struct drm_atomic_state *state,
- struct drm_encoder *new_encoder)
-{
- struct drm_connector *connector;
- struct drm_connector_state *conn_state;
- int i;
-
- for_each_connector_in_state(state, connector, conn_state, i) {
- if (conn_state->best_encoder != new_encoder)
- continue;
-
- /* encoder already assigned and we're trying to re-steal it! */
- if (connector->state->best_encoder != conn_state->best_encoder)
- return false;
- }
-
- return true;
-}
-
static void
set_best_encoder(struct drm_atomic_state *state,
struct drm_connector_state *conn_state,
@@ -325,13 +343,6 @@ update_connector_routing(struct drm_atomic_state *state,
return 0;
}

- if (!check_pending_encoder_assignment(state, new_encoder)) {
- DRM_DEBUG_ATOMIC("Encoder for [CONNECTOR:%d:%s] already assigned\n",
- connector->base.id,
- connector->name);
- return -EINVAL;
- }
-
ret = steal_encoder(state, new_encoder);
if (ret) {
DRM_DEBUG_ATOMIC("Encoder stealing failed for [CONNECTOR:%d:%s]\n",
@@ -510,11 +521,9 @@ drm_atomic_helper_check_modeset(struct drm_device *dev,
}
}

- if (state->legacy_set_config) {
- ret = disable_conflicting_connectors(state);
- if (ret)
- return ret;
- }
+ ret = handle_conflicting_encoders(state, state->legacy_set_config);
+ if (ret)
+ return ret;

for_each_connector_in_state(state, connector, connector_state, i) {
/*