diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c
index d5680a0..275b26a 100644
--- a/drivers/gpu/drm/radeon/radeon_drv.c
+++ b/drivers/gpu/drm/radeon/radeon_drv.c
@@ -48,7 +48,7 @@
  * - 2.5.0 - add get accel 2 to work around ddx breakage for evergreen
  * - 2.6.0 - add tiling config query (r6xx+), add initial HiZ support (r300->r500)
  *   2.7.0 - fixups for r600 2D tiling support. (no external ABI change), add eg dyn gpr regs
- *   2.8.0 - pageflip support, r500 US_FORMAT regs. r500 ARGB2101010 colorbuf, r300->r500 CMASK
+ *   2.8.0 - pageflip support, r500 US_FORMAT regs. r500 ARGB2101010 colorbuf, r300->r500 CMASK, clock crystal query
  */
 #define KMS_DRIVER_MAJOR	2
 #define KMS_DRIVER_MINOR	8
diff --git a/drivers/gpu/drm/radeon/radeon_kms.c b/drivers/gpu/drm/radeon/radeon_kms.c
index 28a53e4a..9832129 100644
--- a/drivers/gpu/drm/radeon/radeon_kms.c
+++ b/drivers/gpu/drm/radeon/radeon_kms.c
@@ -201,6 +201,10 @@
 		}
 		radeon_set_filp_rights(dev, &rdev->cmask_filp, filp, &value);
 		break;
+	case RADEON_INFO_CLOCK_CRYSTAL_FREQ:
+		/* return clock value in KHz */
+		value = rdev->clock.spll.reference_freq * 10;
+		break;
 	default:
 		DRM_DEBUG_KMS("Invalid request %d\n", info->request);
 		return -EINVAL;
diff --git a/include/drm/radeon_drm.h b/include/drm/radeon_drm.h
index e95a86b..e5c607a 100644
--- a/include/drm/radeon_drm.h
+++ b/include/drm/radeon_drm.h
@@ -907,6 +907,7 @@
 #define RADEON_INFO_TILING_CONFIG	0x06
 #define RADEON_INFO_WANT_HYPERZ		0x07
 #define RADEON_INFO_WANT_CMASK		0x08 /* get access to CMASK on r300 */
+#define RADEON_INFO_CLOCK_CRYSTAL_FREQ	0x09 /* clock crystal frequency */
 
 struct drm_radeon_info {
 	uint32_t		request;