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

3 files changed, 79 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index bd62c959b475..b096c1673969 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/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
  */
diff --git a/drivers/gpu/drm/drm_debugfs.c b/drivers/gpu/drm/drm_debugfs.c
index 800055c39cdb..206a4fe7ea26 100644
--- a/drivers/gpu/drm/drm_debugfs.c
+++ b/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) {
diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
index 2d1e9c944b54..331bb100b718 100644
--- a/include/drm/drm_atomic.h
+++ b/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 &&                                \