diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c
index 4b05563d99e16335f729cd3b5fe5bcbff683669f..6e22815f7f07e718c91815baaddd2a3cc72ee55c 100644
--- a/drivers/gpu/drm/radeon/radeon_drv.c
+++ b/drivers/gpu/drm/radeon/radeon_drv.c
@@ -44,9 +44,10 @@
  * - 2.1.0 - add square tiling interface
  * - 2.2.0 - add r6xx/r7xx const buffer support
  * - 2.3.0 - add MSPOS + 3D texture + r500 VAP regs
+ * - 2.4.0 - add crtc id query
  */
 #define KMS_DRIVER_MAJOR	2
-#define KMS_DRIVER_MINOR	3
+#define KMS_DRIVER_MINOR	4
 #define KMS_DRIVER_PATCHLEVEL	0
 int radeon_driver_load_kms(struct drm_device *dev, unsigned long flags);
 int radeon_driver_unload_kms(struct drm_device *dev);
diff --git a/drivers/gpu/drm/radeon/radeon_kms.c b/drivers/gpu/drm/radeon/radeon_kms.c
index d3657dcfdd26335ea9b1ed26e5df4a8d57b52094..021572a3dd9cfd61b8afe98012c498aa7d2ad5e5 100644
--- a/drivers/gpu/drm/radeon/radeon_kms.c
+++ b/drivers/gpu/drm/radeon/radeon_kms.c
@@ -98,11 +98,15 @@ int radeon_info_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
 {
 	struct radeon_device *rdev = dev->dev_private;
 	struct drm_radeon_info *info;
+	struct radeon_mode_info *minfo = &rdev->mode_info;
 	uint32_t *value_ptr;
 	uint32_t value;
+	struct drm_crtc *crtc;
+	int i, found;
 
 	info = data;
 	value_ptr = (uint32_t *)((unsigned long)info->value);
+	value = *value_ptr;
 	switch (info->request) {
 	case RADEON_INFO_DEVICE_ID:
 		value = dev->pci_device;
@@ -116,6 +120,20 @@ int radeon_info_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
 	case RADEON_INFO_ACCEL_WORKING:
 		value = rdev->accel_working;
 		break;
+	case RADEON_INFO_CRTC_FROM_ID:
+		for (i = 0, found = 0; i < rdev->num_crtc; i++) {
+			crtc = (struct drm_crtc *)minfo->crtcs[i];
+			if (crtc && crtc->base.id == value) {
+				value = i;
+				found = 1;
+				break;
+			}
+		}
+		if (!found) {
+			DRM_DEBUG("unknown crtc id %d\n", value);
+			return -EINVAL;
+		}
+		break;
 	default:
 		DRM_DEBUG("Invalid request %d\n", info->request);
 		return -EINVAL;
diff --git a/include/drm/radeon_drm.h b/include/drm/radeon_drm.h
index 81e614bf2dc3ac68accc19b825bf59bff066c913..3ff9fc071dfee1eff45bda07e5ba208af3666c46 100644
--- a/include/drm/radeon_drm.h
+++ b/include/drm/radeon_drm.h
@@ -902,6 +902,7 @@ struct drm_radeon_cs {
 #define RADEON_INFO_NUM_GB_PIPES	0x01
 #define RADEON_INFO_NUM_Z_PIPES 	0x02
 #define RADEON_INFO_ACCEL_WORKING	0x03
+#define RADEON_INFO_CRTC_FROM_ID	0x04
 
 struct drm_radeon_info {
 	uint32_t		request;