Fix really wacky edge case when switching to Auto FrameSkip from "skip buffered" mode.

Fixes issue #20596

Core/Config.cpp

@@ -1460,9 +1460,6 @@ void Config::PostLoadCleanup(bool gameSpecific) {
 	if (g_Config.sCustomDriver == "Default") {
 		g_Config.sCustomDriver = "";
 	}
-
-	// Convert old volume settings.
-
 }
 
 void Config::PreSaveCleanup(bool gameSpecific) {

Core/HLE/sceDisplay.cpp

@@ -425,7 +425,7 @@ static void DoFrameTiming(bool throttle, bool *skipFrame, float scaledTimestep,
 
 	// Auto-frameskip automatically if speed limit is set differently than the default.
 	int frameSkipNum = DisplayCalculateFrameSkip();
-	if (g_Config.bAutoFrameSkip) {
+	if (g_Config.bAutoFrameSkip && !g_Config.bSkipBufferEffects) {
 		// autoframeskip
 		// Argh, we are falling behind! Let's skip a frame and see if we catch up.
 		if (curFrameTime > nextFrameTime && doFrameSkip) {
@@ -694,6 +694,14 @@ void __DisplayFlip(int cyclesLate) {
 	} else {
 		gstate_c.skipDrawReason &= ~SKIPDRAW_SKIPFRAME;
 		numSkippedFrames = 0;
+
+		// NOTE!! It can happen that if we just toggled frameskip (especially auto), we are still in a state
+		// where we don't have a framebuffer bound, from the last frame. But framebuffermanager still might think
+		// that we're in non-buffered mode.
+		if (gpu->GetFramebufferManagerCommon() && !gpu->GetFramebufferManagerCommon()->UseBufferedRendering() && !g_Config.bSkipBufferEffects) {
+			gpu->GetFramebufferManagerCommon()->ForceUseBufferedRendering(!g_Config.bSkipBufferEffects);
+			gstate_c.skipDrawReason &= ~SKIPDRAW_NON_DISPLAYED_FB;
+		}
 	}
 
 	// Returning here with coreState == CORE_NEXTFRAME causes a buffer flip to happen (next frame).

GPU/Common/FramebufferManagerCommon.cpp

@@ -1707,6 +1707,8 @@ void FramebufferManagerCommon::CopyDisplayToOutput(bool reallyDirty) {
 	} else if (useBufferedRendering_) {
 		WARN_LOG(Log::FrameBuf, "Using buffered rendering, and current VFB lacks an FBO: %08x", vfb->fb_address);
 	} else {
+		// This is OK because here we're in "skip buffered" mode, so even if we haven't presented
+		// we will have a render target.
 		presentation_->NotifyPresent();
 	}
 

GPU/Common/FramebufferManagerCommon.h

@@ -385,6 +385,10 @@ public:
 		return useBufferedRendering_;
 	}
 
+	void ForceUseBufferedRendering(bool buf) {
+		useBufferedRendering_ = true;
+	}
+
 	// TODO: Maybe just include the last depth buffer address in this, too.
 	bool MayIntersectFramebufferColor(u32 start) const {
 		// Clear the cache/kernel bits.