From 24ea6a232a239218e7bd2ee23368ead4e7645f4c Mon Sep 17 00:00:00 2001
From: htfab <mpw@htamas.net>
Date: Thu, 12 Mar 2026 21:43:13 +0100
Subject: [PATCH] fix(precheck): force single-threaded mode in sky130A_mr.drc

avoids intermittent segfaults in klayout FEOL check
---
 precheck/precheck.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/precheck/precheck.py b/precheck/precheck.py
index 0fa7865..9b5dfec 100644
--- a/precheck/precheck.py
+++ b/precheck/precheck.py
@@ -102,6 +102,7 @@ def klayout_drc(gds: str, check: str, script=f"{PDK_NAME}_mr.drc", extra_vars=[]
     script_vars = {
         check: "true",
         "input": gds,
+        "thr": "1",  # single-threaded operation in sky130A_mr.drc to work around klayout bug
     }
     script_vars.update(extra_vars)
     klayout_custom_drc(check, script, script_vars, ["report", "report_file"])