diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index d503612a7fc11196823e4277ee60a636c3bc4b9c..a534412a5551d467043480d7a28332dfe8d69a09 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -379,6 +379,11 @@ static int i915_getparam(struct drm_device *dev, void *data,
 		if (!value)
 			return -ENODEV;
 		break;
+	case I915_PARAM_SUBSLICE_MASK:
+		value = INTEL_INFO(dev_priv)->sseu.subslice_mask;
+		if (!value)
+			return -ENODEV;
+		break;
 	default:
 		DRM_DEBUG("Unknown parameter %d\n", param->param);
 		return -EINVAL;
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 25695c3d9a76bd22fc5951ddbb7d00307af66e9c..464547d0817389fe63cf61d032d49a17f0b13523 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -421,6 +421,11 @@ typedef struct drm_i915_irq_wait {
 /* Query the mask of slices available for this system */
 #define I915_PARAM_SLICE_MASK		 46
 
+/* Assuming it's uniform for each slice, this queries the mask of subslices
+ * per-slice for this system.
+ */
+#define I915_PARAM_SUBSLICE_MASK	 47
+
 typedef struct drm_i915_getparam {
 	__s32 param;
 	/*