From 7d246837879102fe5c18e40b2fed73af34ca07dc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=A9ana=20=E6=B1=9F?= <leana.jiang+git@icloud.com>
Date: Sat, 6 Sep 2025 11:12:33 +0800
Subject: [PATCH] vanadium: set ddc brightness with autorandr

---
 nix/configurations/vanadium/nixos/display.nix | 20 ++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/nix/configurations/vanadium/nixos/display.nix b/nix/configurations/vanadium/nixos/display.nix
index c6e1c3c6..476195d8 100644
--- a/nix/configurations/vanadium/nixos/display.nix
+++ b/nix/configurations/vanadium/nixos/display.nix
@@ -58,13 +58,23 @@
 
         # Is scoped to an output device, no need to be called on built-in display
         setSoftwareBrightness = {
-          device,
-          brightness,
+          device, # obtain with `xrandr`
+          brightness, # [0..1]
         }: {
           "10_xrandr_brightness" = ''
             xrandr --output ${device} --brightness ${toString brightness}
           '';
         };
+
+        # Is scoped to an output device, no need to be called on built-in display
+        setDDCBrightness = {
+          modelName, # obtain with `ddcutil detect`
+          brightness, # [0..1]
+        }: {
+          "10_ddc_brightness" = ''
+            ddcutil --model ${modelName} setvcp 10 ${toString (brightness * 100)}
+          '';
+        };
       };
 
       # Note: the "position" field corresponds to the "pos" field outputted by autorandr
@@ -106,9 +116,13 @@
         config = with configs; allOff // enableDevice name;
         hooks.postswitch = with switches;
           setDPI {dpi = 110;}
+          // setDDCBrightness {
+            modelName = "VG27AQL3A";
+            brightness = 0;
+          }
           // setSoftwareBrightness {
             device = name;
-            brightness = 0.7; # just a random sensible choice
+            brightness = 0.7;
           };
       };
     in