[PATCH v14 09/41] compositor-drm: Track unused connectors and CRTCs

[Daniel Stone]

Rather than a more piecemeal approach at backend creation, explicitly
track connectors and CRTCs we do not intend to use, so we can ensure
they are disabled where appropriate.

Signed-off-by: Daniel Stone <daniels at collabora.com>
---
 libweston/compositor-drm.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)

diff --git a/libweston/compositor-drm.c b/libweston/compositor-drm.c
index 04d52f2c6..9c7564383 100644
--- a/libweston/compositor-drm.c
+++ b/libweston/compositor-drm.c
@@ -188,6 +188,9 @@ struct drm_backend {
 
 	void *repaint_data;
 
+	struct wl_array unused_connectors;
+	struct wl_array unused_crtcs;
+
 	int cursors_are_broken;
 
 	bool universal_planes;
@@ -386,6 +389,26 @@ static struct gl_renderer_interface *gl_renderer;
 
 static const char default_seat[] = "seat0";
 
+static void
+wl_array_remove_uint32(struct wl_array *array, uint32_t elm)
+{
+	uint32_t *pos, *end;
+
+	end = (uint32_t *) ((char *) array->data + array->size);
+
+	wl_array_for_each(pos, array) {
+		if (*pos != elm)
+			continue;
+
+		array->size -= sizeof(*pos);
+		if (pos + 1 == end)
+			break;
+
+		memmove(pos, pos + 1, (char *) end -  (char *) (pos + 1));
+		break;
+	}
+}
+
 static inline struct drm_output *
 to_drm_output(struct weston_output *base)
 {
@@ -1327,6 +1350,7 @@ drm_output_assign_state(struct drm_output_state *state,
 			enum drm_state_apply_mode mode)
 {
 	struct drm_output *output = state->output;
+	struct drm_backend *b = to_drm_backend(output->base.compositor);
 	struct drm_plane_state *plane_state;
 
 	assert(!output->state_last);
@@ -1363,6 +1387,12 @@ drm_output_assign_state(struct drm_output_state *state,
 		else if (plane->type == WDRM_PLANE_TYPE_PRIMARY)
 			output->page_flip_pending = 1;
 	}
+
+	if (output->dpms == WESTON_DPMS_ON) {
+		wl_array_remove_uint32(&b->unused_connectors,
+				       output->connector_id);
+		wl_array_remove_uint32(&b->unused_crtcs, output->crtc_id);
+	}
 }
 
 
@@ -3983,6 +4013,7 @@ drm_output_deinit(struct weston_output *base)
 {
 	struct drm_output *output = to_drm_output(base);
 	struct drm_backend *b = to_drm_backend(base->compositor);
+	uint32_t *unused;
 
 	if (b->use_pixman)
 		drm_output_fini_pixman(output);
@@ -4004,6 +4035,11 @@ drm_output_deinit(struct weston_output *base)
 			drmModeSetCursor(b->drm.fd, output->crtc_id, 0, 0, 0);
 		}
 	}
+
+	unused = wl_array_add(&b->unused_connectors, sizeof(*unused));
+	*unused = output->connector_id;
+	unused = wl_array_add(&b->unused_crtcs, sizeof(*unused));
+	*unused = output->crtc_id;
 }
 
 static void
@@ -4099,6 +4135,47 @@ drm_output_disable(struct weston_output *base)
 	return 0;
 }
 
+/**
+ * Update the list of unused connectors and CRTCs
+ *
+ * This keeps the unused_connectors and unused_crtcs arrays up to date.
+ *
+ * @param b Weston backend structure
+ * @param resources DRM resources for this device
+ */
+static void
+drm_backend_update_unused_outputs(struct drm_backend *b, drmModeRes *resources)
+{
+	int i;
+
+	wl_array_release(&b->unused_connectors);
+	wl_array_init(&b->unused_connectors);
+
+	for (i = 0; i < resources->count_connectors; i++) {
+		uint32_t *connector_id;
+
+		if (drm_output_find_by_connector(b, resources->connectors[i]))
+			continue;
+
+		connector_id = wl_array_add(&b->unused_connectors,
+					    sizeof(*connector_id));
+		*connector_id = resources->connectors[i];
+	}
+
+	wl_array_release(&b->unused_crtcs);
+	wl_array_init(&b->unused_crtcs);
+
+	for (i = 0; i < resources->count_crtcs; i++) {
+		uint32_t *crtc_id;
+
+		if (drm_output_find_by_crtc(b, resources->crtcs[i]))
+			continue;
+
+		crtc_id = wl_array_add(&b->unused_crtcs, sizeof(*crtc_id));
+		*crtc_id = resources->crtcs[i];
+	}
+}
+
 /**
  * Create a Weston output structure
  *
@@ -4259,6 +4336,8 @@ create_outputs(struct drm_backend *b, struct udev_device *drm_device)
 		}
 	}
 
+	drm_backend_update_unused_outputs(b, resources);
+
 	if (wl_list_empty(&b->compositor->output_list) &&
 	    wl_list_empty(&b->compositor->pending_output_list))
 		weston_log("No currently active connector found.\n");
@@ -4350,6 +4429,8 @@ update_outputs(struct drm_backend *b, struct udev_device *drm_device)
 		drm_output_destroy(&output->base);
 	}
 
+	drm_backend_update_unused_outputs(b, resources);
+
 	free(connected);
 	drmModeFreeResources(resources);
 }
@@ -4416,6 +4497,9 @@ drm_destroy(struct weston_compositor *ec)
 
 	weston_launcher_destroy(ec->launcher);
 
+	wl_array_release(&b->unused_crtcs);
+	wl_array_release(&b->unused_connectors);
+
 	close(b->drm.fd);
 	free(b);
 }
@@ -4848,6 +4932,8 @@ drm_backend_create(struct weston_compositor *compositor,
 		return NULL;
 
 	b->drm.fd = -1;
+	wl_array_init(&b->unused_crtcs);
+	wl_array_init(&b->unused_connectors);
 
 	/*
 	 * KMS support for hardware planes cannot properly synchronize
-- 
2.14.3