From cca70642e857b9010640da2b6dc2eddfa06a7603 Mon Sep 17 00:00:00 2001
From: Peng Mei Yu <pengmeiyu@riseup.net>
Date: Tue, 9 Mar 2021 12:32:58 +0800
Subject: [PATCH] ThinkPad X270: Disable Panel Self Refresh.

---
 lenovo/thinkpad/x270/default.nix | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/lenovo/thinkpad/x270/default.nix b/lenovo/thinkpad/x270/default.nix
index 870d9a8..af4991b 100644
--- a/lenovo/thinkpad/x270/default.nix
+++ b/lenovo/thinkpad/x270/default.nix
@@ -3,4 +3,9 @@
     ../.
     ../../../common/cpu/intel
   ];
+
+  boot.kernelParams = [
+    # Disable "Panel Self Refresh".  Fix random freezes.
+    "i915.enable_psr=0"
+  ];
 }