drm: Add helpers to turn off CRTCs

Turning off a single CRTC or all active CRTCs of a DRM device is a
fairly common pattern. Add helpers to avoid open coding this everywhere.

The name was chosen to be consistent with drm_plane_force_disable().

Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index fd93e9c..c7d9925 100644 (file)
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -396,6 +396,51 @@ void drm_mode_object_reference(struct drm_mode_object *obj)
 }
 EXPORT_SYMBOL(drm_mode_object_reference);
 
+/**
+ * drm_crtc_force_disable - Forcibly turn off a CRTC
+ * @crtc: CRTC to turn off
+ *
+ * Returns:
+ * Zero on success, error code on failure.
+ */
+int drm_crtc_force_disable(struct drm_crtc *crtc)
+{
+       struct drm_mode_set set = {
+               .crtc = crtc,
+       };
+
+       return drm_mode_set_config_internal(&set);
+}
+EXPORT_SYMBOL(drm_crtc_force_disable);
+
+/**
+ * drm_crtc_force_disable_all - Forcibly turn off all enabled CRTCs
+ * @dev: DRM device whose CRTCs to turn off
+ *
+ * Drivers may want to call this on unload to ensure that all displays are
+ * unlit and the GPU is in a consistent, low power state. Takes modeset locks.
+ *
+ * Returns:
+ * Zero on success, error code on failure.
+ */
+int drm_crtc_force_disable_all(struct drm_device *dev)
+{
+       struct drm_crtc *crtc;
+       int ret = 0;
+
+       drm_modeset_lock_all(dev);
+       drm_for_each_crtc(crtc, dev)
+               if (crtc->enabled) {
+                       ret = drm_crtc_force_disable(crtc);
+                       if (ret)
+                               goto out;
+               }
+out:
+       drm_modeset_unlock_all(dev);
+       return ret;
+}
+EXPORT_SYMBOL(drm_crtc_force_disable_all);
+
 static void drm_framebuffer_free(struct kref *kref)
 {
        struct drm_framebuffer *fb =

diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index f5469d3..781695c 100644 (file)
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -2654,6 +2654,8 @@ extern struct drm_plane * drm_plane_from_index(struct drm_device *dev, int idx);
 extern void drm_plane_force_disable(struct drm_plane *plane);
 extern void drm_crtc_get_hv_timing(const struct drm_display_mode *mode,
                                   int *hdisplay, int *vdisplay);
+extern int drm_crtc_force_disable(struct drm_crtc *crtc);
+extern int drm_crtc_force_disable_all(struct drm_device *dev);
 
 extern void drm_encoder_cleanup(struct drm_encoder *encoder);