drm/atomic: add debugfs file to dump out atomic state

Useful to dump current state from debugfs, if turning on the drm.debug
bit is too much overhead.

The drm_state_dump() can also be used by drivers, for example to
implement a module param that dumps state on error irqs.

Signed-off-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1478358492-30738-6-git-send-email-robdclark@gmail.com

drivers/gpu/drm/drm_atomic.c

@@ -1577,6 +1577,69 @@ static void drm_atomic_print_state(const struct drm_atomic_state *state)
 		drm_atomic_connector_print_state(&p, connector_state);
 }
 
+/**
+ * drm_state_dump - dump entire device atomic state
+ * @dev: the drm device
+ * @p: where to print the state to
+ *
+ * Just for debugging.  Drivers might want an option to dump state
+ * to dmesg in case of error irq's.  (Hint, you probably want to
+ * ratelimit this!)
+ *
+ * The caller must drm_modeset_lock_all(), or if this is called
+ * from error irq handler, it should not be enabled by default.
+ * (Ie. if you are debugging errors you might not care that this
+ * is racey.  But calling this without all modeset locks held is
+ * not inherently safe.)
+ */
+void drm_state_dump(struct drm_device *dev, struct drm_printer *p)
+{
+	struct drm_mode_config *config = &dev->mode_config;
+	struct drm_plane *plane;
+	struct drm_crtc *crtc;
+	struct drm_connector *connector;
+
+	if (!drm_core_check_feature(dev, DRIVER_ATOMIC))
+		return;
+
+	list_for_each_entry(plane, &config->plane_list, head)
+		drm_atomic_plane_print_state(p, plane->state);
+
+	list_for_each_entry(crtc, &config->crtc_list, head)
+		drm_atomic_crtc_print_state(p, crtc->state);
+
+	list_for_each_entry(connector, &config->connector_list, head)
+		drm_atomic_connector_print_state(p, connector->state);
+}
+EXPORT_SYMBOL(drm_state_dump);
+
+#ifdef CONFIG_DEBUG_FS
+static int drm_state_info(struct seq_file *m, void *data)
+{
+	struct drm_info_node *node = (struct drm_info_node *) m->private;
+	struct drm_device *dev = node->minor->dev;
+	struct drm_printer p = drm_seq_file_printer(m);
+
+	drm_modeset_lock_all(dev);
+	drm_state_dump(dev, &p);
+	drm_modeset_unlock_all(dev);
+
+	return 0;
+}
+
+/* any use in debugfs files to dump individual planes/crtc/etc? */
+static const struct drm_info_list drm_atomic_debugfs_list[] = {
+	{"state", drm_state_info, 0},
+};
+
+int drm_atomic_debugfs_init(struct drm_minor *minor)
+{
+	return drm_debugfs_create_files(drm_atomic_debugfs_list,
+			ARRAY_SIZE(drm_atomic_debugfs_list),
+			minor->debugfs_root, minor);
+}
+#endif
+
 /*
  * The big monstor ioctl
  */

drivers/gpu/drm/drm_debugfs.c

@@ -36,6 +36,7 @@
 #include <linux/export.h>
 #include <drm/drmP.h>
 #include <drm/drm_edid.h>
+#include <drm/drm_atomic.h>
 #include "drm_internal.h"
 
 #if defined(CONFIG_DEBUG_FS)
@@ -163,6 +164,14 @@ int drm_debugfs_init(struct drm_minor *minor, int minor_id,
 		return ret;
 	}
 
+	if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
+		ret = drm_atomic_debugfs_init(minor);
+		if (ret) {
+			DRM_ERROR("Failed to create atomic debugfs files\n");
+			return ret;
+		}
+	}
+
 	if (dev->driver->debugfs_init) {
 		ret = dev->driver->debugfs_init(minor);
 		if (ret) {

include/drm/drm_atomic.h

@@ -366,6 +366,13 @@ int __must_check drm_atomic_check_only(struct drm_atomic_state *state);
 int __must_check drm_atomic_commit(struct drm_atomic_state *state);
 int __must_check drm_atomic_nonblocking_commit(struct drm_atomic_state *state);
 
+void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
+
+#ifdef CONFIG_DEBUG_FS
+struct drm_minor;
+int drm_atomic_debugfs_init(struct drm_minor *minor);
+#endif
+
 #define for_each_connector_in_state(__state, connector, connector_state, __i) \
 	for ((__i) = 0;							\
 	     (__i) < (__state)->num_connector &&				\