From b416c1d56f33bf902625b2cd0ee43dbc59fc64dd Mon Sep 17 00:00:00 2001
From: Marien Zwart <marien.zwart@gmail.com>
Date: Mon, 24 Feb 2025 21:23:15 +1100
Subject: [PATCH] Simplify implementation of B550 suspend fix

Instead of using systemd oneshot services that have to be careful to not
toggle wakeups back on, use a udev rule to disable wakeups by device ID.

On a B550 Vision D, these do almost the same thing:

````
$ lspci -n | grep 1022:1483
00:01.1 0604: 1022:1483
00:01.2 0604: 1022:1483
00:03.1 0604: 1022:1483

$ cat /proc/acpi/wakeup
Device  S-state   Status   Sysfs node
...
GPP0      S4    *disabled  pci:0000:00:01.1
GPP8      S4    *disabled  pci:0000:00:03.1
````

Two of the three devices with the PCI vendor/device ID specified by the
udev rule correspond to devices previously disabled via ACPI (if I
understand correctly disabling these via either /proc/acpi/wakeup or
udev device attribute has the same effect).

The third device is (like the other two) using the "pcieport" driver.
Using a device connected via that port as a wakeup device still works.
---
 gigabyte/b550/b550-fix-suspend.nix | 44 ++++++++----------------------
 1 file changed, 11 insertions(+), 33 deletions(-)

diff --git a/gigabyte/b550/b550-fix-suspend.nix b/gigabyte/b550/b550-fix-suspend.nix
index 49868093..abc04a2d 100644
--- a/gigabyte/b550/b550-fix-suspend.nix
+++ b/gigabyte/b550/b550-fix-suspend.nix
@@ -1,35 +1,13 @@
-{ pkgs, lib, ... } :
-
 {
-  systemd.services.bugfixSuspend-GPP0 = {
-    enable            = lib.mkDefault true;
-    description       = "Fix crash on wakeup from suspend/hibernate (b550 bugfix)";
-    unitConfig = {
-      Type            = "oneshot";
-    };
-    serviceConfig = {
-      User            = "root"; # root may not be necessary
-      # check for gppN, disable if enabled
-      # lifted from  https://www.reddit.com/r/gigabyte/comments/p5ewjn/comment/ksbm0mb/ /u/Demotay
-      ExecStart       = "-${pkgs.bash}/bin/bash -c 'if grep 'GPP0' /proc/acpi/wakeup | grep -q 'enabled'; then echo 'GPP0' > /proc/acpi/wakeup; fi'"; 
-      RemainAfterExit = "yes";  # required to not toggle when `nixos-rebuild switch` is ran
-      
-    };
-    wantedBy = ["multi-user.target"];
-  };
-
-  systemd.services.bugfixSuspend-GPP8 = {
-    enable            = lib.mkDefault true;
-    description       = "Fix crash on wakeup from suspend/hibernate (b550 bugfix)";
-    unitConfig = {
-      Type            = "oneshot";
-    };
-    serviceConfig = {
-      User            = "root";
-      ExecStart       = "-${pkgs.bash}/bin/bash -c 'if grep 'GPP8' /proc/acpi/wakeup | grep -q 'enabled'; then echo 'GPP8' > /proc/acpi/wakeup; fi'";
-      RemainAfterExit = "yes";
-    };
-    wantedBy = ["multi-user.target"];
-  };
-
+  # Work around an issue causing the system to unsuspend immediately after suspend
+  # and/or hang after suspend.
+  #
+  # See https://www.reddit.com/r/gigabyte/comments/p5ewjn/comment/ksbm0mb/ /u/Demotay
+  #
+  # Most suggestions elsewhere are to disable GPP0 and/or GPP8 using /proc/acpi/wakeup, but that is
+  # inconvenient because it toggles. This does essentially the same thing using udev, which can set
+  # the wakeup attribute to a specific value.
+  services.udev.extraRules = ''
+    ACTION=="add", SUBSYSTEM=="pci", ATTR{vendor}=="0x1022", ATTR{device}=="0x1483", ATTR{power/wakeup}="disabled"
+  '';
 }