diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index 359af0623302..9d60020c5cb3 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -1127,7 +1127,14 @@ static int cxl_port_setup_targets(struct cxl_port *port,
 	}
 
 	if (is_cxl_root(parent_port)) {
-		parent_ig = cxlrd->cxlsd.cxld.interleave_granularity;
+		/*
+		 * Root decoder IG is always set to value in CFMWS which
+		 * may be different than this region's IG.  We can use the
+		 * region's IG here since interleave_granularity_store()
+		 * does not allow interleaved host-bridges with
+		 * root IG != region IG.
+		 */
+		parent_ig = p->interleave_granularity;
 		parent_iw = cxlrd->cxlsd.cxld.interleave_ways;
 		/*
 		 * For purposes of address bit routing, use power-of-2 math for
diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c
index fb6ab9cef84f..b88546299902 100644
--- a/tools/testing/cxl/test/cxl.c
+++ b/tools/testing/cxl/test/cxl.c
@@ -831,7 +831,7 @@ static void mock_init_hdm_decoder(struct cxl_decoder *cxld)
 			cxld->interleave_ways = 2;
 		else
 			cxld->interleave_ways = 1;
-		cxld->interleave_granularity = 256;
+		cxld->interleave_granularity = 4096;
 		cxld->hpa_range = (struct range) {
 			.start = base,
 			.end = base + size - 1,