drm_crtc_helper.c

	if (mode == connector->dpms)
		return;

	old_dpms = connector->dpms;
	connector->dpms = mode;

	/* from off to on, do crtc then encoder */
	if (mode < old_dpms) {
		if (crtc) {
			struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
			if (crtc_funcs->dpms)
				(*crtc_funcs->dpms) (crtc,
						     drm_helper_choose_crtc_dpms(crtc));
		}
		if (encoder) {
			struct drm_encoder_helper_funcs *encoder_funcs = encoder->helper_private;
			if (encoder_funcs->dpms)
				(*encoder_funcs->dpms) (encoder,
							drm_helper_choose_encoder_dpms(encoder));
		}
	}

	/* from on to off, do encoder then crtc */
	if (mode > old_dpms) {
		if (encoder) {
			struct drm_encoder_helper_funcs *encoder_funcs = encoder->helper_private;
			if (encoder_funcs->dpms)
				(*encoder_funcs->dpms) (encoder,
							drm_helper_choose_encoder_dpms(encoder));
		}
		if (crtc) {
			struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
			if (crtc_funcs->dpms)
				(*crtc_funcs->dpms) (crtc,
						     drm_helper_choose_crtc_dpms(crtc));
		}
	}

	return;
}
EXPORT_SYMBOL(drm_helper_connector_dpms);

/**
 * drm_hotplug_stage_two
 * @dev DRM device
 * @connector hotpluged connector
 *
 * LOCKING.
 * Caller must hold mode config lock, function might grab struct lock.
 *
 * Stage two of a hotplug.
 *
 * RETURNS:
 * Zero on success, errno on failure.
 */
int drm_helper_hotplug_stage_two(struct drm_device *dev)
{
	drm_helper_plugged_event(dev);

	return 0;
}
EXPORT_SYMBOL(drm_helper_hotplug_stage_two);

int drm_helper_mode_fill_fb_struct(struct drm_framebuffer *fb,
				   struct drm_mode_fb_cmd *mode_cmd)
{
	fb->width = mode_cmd->width;
	fb->height = mode_cmd->height;
	fb->pitch = mode_cmd->pitch;
	fb->bits_per_pixel = mode_cmd->bpp;
	fb->depth = mode_cmd->depth;

	return 0;
}
EXPORT_SYMBOL(drm_helper_mode_fill_fb_struct);

int drm_helper_resume_force_mode(struct drm_device *dev)
{
	struct drm_crtc *crtc;
	int ret;

	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {

		if (!crtc->enabled)
			continue;

		ret = drm_crtc_helper_set_mode(crtc, &crtc->mode,
					       crtc->x, crtc->y, crtc->fb);

		if (ret == false)
			DRM_ERROR("failed to set mode on crtc %p\n", crtc);
	}
	/* disable the unused connectors while restoring the modesetting */
	drm_helper_disable_unused_functions(dev);
	return 0;
}
EXPORT_SYMBOL(drm_helper_resume_force_mode);