drm/i915: expose _SUBSLICE_MASK GETPARM

Assuming a uniform mask across all slices, this enables userspace to
determine the specific sub slices enabled. This information is required,
for example, to be able to analyse some OA counter reports where the
counter configuration depends on the HW sub slice configuration.

Signed-off-by: Robert Bragg <[email protected]>

Author: rib

drivers/gpu/drm/i915/i915_dma.c

@@ -175,6 +175,11 @@ 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)->subslice_mask;
+		if (!value)
+			return -ENODEV;
+		break;
 	default:
 		DRM_DEBUG("Unknown parameter %d\n", param->param);
 		return -EINVAL;

include/uapi/drm/i915_drm.h

@@ -359,6 +359,7 @@ typedef struct drm_i915_irq_wait {
 #define I915_PARAM_HAS_GPU_RESET	 35
 #define I915_PARAM_HAS_RESOURCE_STREAMER 36
 #define I915_PARAM_SLICE_MASK		 45 /* XXX: rebase before landing */
+#define I915_PARAM_SUBSLICE_MASK	 46
 
 typedef struct drm_i915_getparam {
 	__s32 param;