Ensure that GPU SSID is restored

Change-Id: Iada67ff9b7d882167ca2047a1618230e73d4300d

src/mainboard/system76/galp5/acpi/dgpu.asl

@@ -1,17 +1,30 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
-#define DGPU_RP \_SB.PCI0.RP01
-
-External (DGPU_RP.RTD3)
-
-Device (DGPU_RP.DEV0) {
+Scope (\_SB.PCI0.RP01) {
+    Device (DEV0) {
         Name(_ADR, 0x00000000)
 
-	Method (_PS0, 0) {
-		Debug = "GPU _PS0"
+        OperationRegion (PCIC, PCI_Config, 0x00, 0x50)
+        Field (PCIC, DwordAcc, NoLock, Preserve) {
+            Offset (0x40),
+            SSID, 32
         }
 
-	Method (_PS3, 0) {
-		Debug = "GPU _PS3"
+        Name (_PR0, Package () { PWRR })
+        Name (_PR3, Package () { PWRR })
+        PowerResource (PWRR, 0, 0) {
+            Name (_STA, 1)
+
+            Method (_ON) {
+                ^^SSID = 0x40181558
+                Printf("GPU _ON %o", ToHexString(^^SSID))
+                _STA = 1
+            }
+
+            Method (_OFF) {
+                Printf("GPU _OFF %o", ToHexString(^^SSID))
+                _STA = 0
+            }
+        }
     }
 }