Savestate: Don't change the running game's state when saving

Some DoState code meant for after a load ran on every save:
- scePower reset the bus frequency a game set (and with a locked CPU
  speed, applied the current setting to the clock).
- sceDisplay reset the lag sync baseline, and could schedule lag sync in
  the measuring pass only, which failed the save.
- GPUState dirtied the texture, sceUmd notified the UI, and sceMpeg
  dropped a pending ringbuffer fix-up for an old state.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

Core/HLE/sceDisplay.cpp

@@ -261,9 +261,11 @@ void __DisplayDoState(PointerWrap &p) {
 		Do(p, lagSyncEvent);
 		Do(p, lagSyncScheduled);
 		CoreTiming::RestoreRegisterEvent(lagSyncEvent, "LagSync", &hleLagSync);
-		lastLagSync = time_now_d();
-		if (lagSyncScheduled != UseLagSync()) {
-			ScheduleLagSync();
+		if (p.mode == p.MODE_READ) {
+			lastLagSync = time_now_d();
+			if (lagSyncScheduled != UseLagSync()) {
+				ScheduleLagSync();
+			}
 		}
 	} else {
 		lagSyncEvent = -1;

Core/HLE/sceMpeg.cpp

@@ -230,7 +230,9 @@ void MpegContext::DoState(PointerWrap &p) {
 		}
 	}
 	DoClass(p, mediaengine);
-	ringbufferNeedsReverse = s < 2;
+	if (p.mode == p.MODE_READ) {
+		ringbufferNeedsReverse = s < 2;
+	}
 }
 
 static MpegContext *getMpegCtx(u32 mpegAddr) {

Core/HLE/scePower.cpp

@@ -161,13 +161,15 @@ void __PowerDoState(PointerWrap &p) {
 		RealpllFreq = PowerPllMhzToHz(222);
 		RealbusFreq = PowerBusMhzToHz(111);
 	}
-	if (GetLockedCPUSpeedMhz() > 0) {
-		pllFreq = PowerPllMhzToHz(GetLockedCPUSpeedMhz());
-		busFreq = PowerBusMhzToHz(pllFreq / 2000000);
-		CoreTiming::SetClockFrequencyHz(PowerCpuMhzToHz(GetLockedCPUSpeedMhz(), pllFreq));
-	} else {
-		pllFreq = RealpllFreq;
-		busFreq = RealbusFreq;
+	if (p.mode == p.MODE_READ) {
+		if (GetLockedCPUSpeedMhz() > 0) {
+			pllFreq = PowerPllMhzToHz(GetLockedCPUSpeedMhz());
+			busFreq = PowerBusMhzToHz(pllFreq / 2000000);
+			CoreTiming::SetClockFrequencyHz(PowerCpuMhzToHz(GetLockedCPUSpeedMhz(), pllFreq));
+		} else {
+			pllFreq = RealpllFreq;
+			busFreq = RealbusFreq;
+		}
 	}
 	DoArray(p, powerCbSlots, ARRAY_SIZE(powerCbSlots));
 	Do(p, volatileMemLocked);

Core/HLE/sceUmd.cpp

@@ -106,7 +106,7 @@ void __UmdDoState(PointerWrap &p)
 
 	if (s > 1) {
 		Do(p, g_UMDReplacePermit);
-		if (g_UMDReplacePermit) {
+		if (g_UMDReplacePermit && p.mode == p.MODE_READ) {
 			System_Notify(SystemNotification::UI);
 		}
 	}

GPU/GPUState.cpp

@@ -301,7 +301,9 @@ void GPUStateCache::DoState(PointerWrap &p) {
 
 		uint8_t textureChanged = 0;
 		Do(p, textureChanged);  // legacy
-		gstate_c.Dirty(DIRTY_TEXTURE_IMAGE | DIRTY_TEXTURE_PARAMS);
+		if (p.mode == p.MODE_READ) {
+			gstate_c.Dirty(DIRTY_TEXTURE_IMAGE | DIRTY_TEXTURE_PARAMS);
+		}
 		Do(p, textureSolidAlpha);
 		Do(p, vertexFullAlpha);
 		bool framebufChanged = false;  // legacy