From c06e6d4cd1db23940e1b578349bbf0a3e90a3932 Mon Sep 17 00:00:00 2001
From: teutat3s <teutates@mailbox.org>
Date: Fri, 5 May 2023 18:13:19 +0200
Subject: [PATCH] dumpyourvms: linux 6.4 amdgpu switcheroo fixes

---
 hosts/dumpyourvms/dumpyourvms.nix | 38 ++++++++++++++++---------------
 1 file changed, 20 insertions(+), 18 deletions(-)

diff --git a/hosts/dumpyourvms/dumpyourvms.nix b/hosts/dumpyourvms/dumpyourvms.nix
index 17b7597f..aed265fa 100644
--- a/hosts/dumpyourvms/dumpyourvms.nix
+++ b/hosts/dumpyourvms/dumpyourvms.nix
@@ -36,9 +36,7 @@ in {
     # Explicitly set amdgpu support in place of radeon
     # Source: https://github.com/NixOS/nixos-hardware/blob/master/common/gpu/amd/southern-islands/default.nix
     # Try again after https://lists.freedesktop.org/archives/amd-gfx/2023-March/090096.html lands
-    # Maybe linux kernel 6.3?
-    #boot.kernelParams = ["acpi_backlight=video" "hid_apple.fnmode=2" "intel_pstate=passive" "radeon.si_support=0" "amdgpu.si_support=1"];
-    boot.kernelParams = ["acpi_backlight=video" "hid_apple.fnmode=2" "intel_pstate=passive"];
+    boot.kernelParams = ["acpi_backlight=video" "hid_apple.fnmode=2" "intel_pstate=passive" "radeon.si_support=0" "amdgpu.si_support=1"];
     boot.loader.efi.canTouchEfiVariables = true;
 
     # Fix for Error switching console mode to 1: unsupported on startup
@@ -80,29 +78,22 @@ in {
     # https://ubuntuforums.org/showthread.php?t=2409856
     services.cron.systemCronJobs = [
       "@reboot root ${pkgs.util-linux}/bin/rfkill block bluetooth"
-      "@reboot root ${pkgs.coreutils}/bin/sleep 11; ${pkgs.coreutils}/bin/echo 510 > /sys/class/backlight/gmux_backlight/brightness"
     ];
 
     # Disable dedicated GPU, use integrated Intel GPU to save battery
     # https://github.com/NixOS/nixpkgs/pull/33915
-    systemd.services."amd-hybrid-graphics" = {
-      path = [pkgs.bash];
-      description = "Disable AMD Card";
+    systemd.services."amd-hybrid-graphics-power-save" = {
+      path = [pkgs.bash pkgs.coreutils];
+      description = "Power Off dedicated AMD Card to reduce power usage";
       after = ["sys-kernel-debug.mount"];
       before = ["systemd-vconsole-setup.service" "display-manager.service"];
-      requires = ["sys-kernel-debug.mount" "vgaswitcheroo.path"];
+      requires = ["sys-kernel-debug.mount"];
       serviceConfig = {
         Type = "oneshot";
         RemainAfterExit = true;
-        ExecStart = "${pkgs.bash}/bin/sh -c 'echo -e \"IGD\\nOFF\" > /sys/kernel/debug/vgaswitcheroo/switch'";
+        ExecStart = "${pkgs.bash}/bin/sh -c 'sleep 8 && echo -e \"IGD\\nOFF\" > /sys/kernel/debug/vgaswitcheroo/switch'";
         ExecStop = "${pkgs.bash}/bin/sh -c 'echo ON >/sys/kernel/debug/vgaswitcheroo/switch'";
       };
-    };
-    systemd.paths."vgaswitcheroo" = {
-      pathConfig = {
-        PathExists = "/sys/kernel/debug/vgaswitcheroo/switch";
-        Unit = "amd-hybrid-graphics.service";
-      };
       wantedBy = ["multi-user.target"];
     };
 
@@ -125,12 +116,20 @@ in {
       # brcmfmac being loaded during hibernation would inhibit a successful resume
       # https://bugzilla.kernel.org/show_bug.cgi?id=101681#c116.
       # Also brcmfmac could randomly crash on resume from sleep.
+      # For hibernate successfully using the amdgpu driver, the dedicated GPU needs
+      # to be powered on.
       powerUpCommands = lib.mkBefore ("${pkgs.kmod}/bin/modprobe brcmfmac"
         + lib.optionalString
         (lib.versionAtLeast config.boot.kernelPackages.kernel.version "6.2") " brcmfmac_wcc");
-      powerDownCommands = lib.mkBefore ("${pkgs.kmod}/bin/rmmod brcmfmac"
-        + lib.optionalString
-        (lib.versionAtLeast config.boot.kernelPackages.kernel.version "6.2") " brcmfmac_wcc");
+      powerDownCommands = lib.mkBefore (
+        lib.optionalString
+        (lib.versionAtLeast config.boot.kernelPackages.kernel.version "6.2")
+        "${pkgs.kmod}/bin/rmmod brcmfmac_wcc\n"
+        + ''
+          ${pkgs.kmod}/bin/rmmod brcmfmac
+          ${pkgs.systemd}/bin/systemctl stop amd-hybrid-graphics-power-save.service
+        ''
+      );
     };
 
     # Change lid switch behaviour
@@ -175,6 +174,9 @@ in {
     hardware.firmware = with pkgs; [wireless-regdb];
     boot.extraModprobeConfig = ''
       options cfg80211 ieee80211_regdom="DE"
+
+      # Enable the integrated GPU (iGPU) Intel i915 by default if present
+      options apple-gmux force_igd=y
     '';
 
     # This value determines the NixOS release from which the default