LCD Update performance fix to avoid glitches on single core RPis

src/minidexed.cpp

@@ -701,7 +701,10 @@ void CMiniDexed::setInsertFXType (unsigned nType, unsigned nTG)
 	}
 
 	m_InsertFXSpinLock[nTG]->Acquire();
-	delete m_InsertFX[nTG];
+	if (m_InsertFX[nTG] != NULL)
+	{
+		delete m_InsertFX[nTG];
+	}
 	m_InsertFX[nTG] = newAudioEffect(nType, m_pConfig->GetSampleRate());
 	m_InsertFX[nTG]->setTempo(m_nTempo);
 	m_InsertFXSpinLock[nTG]->Release();

src/userinterface.cpp

@@ -53,6 +53,7 @@ CUserInterface::~CUserInterface (void)
 bool CUserInterface::Initialize (void)
 {
 	assert (m_pConfig);
+	nLastLCDUpdateTime = 0;
 
 	if (m_pConfig->GetLCDEnabled ())
 	{
@@ -152,7 +153,7 @@ bool CUserInterface::Initialize (void)
 		}
 		assert (m_pLCD);
 
-		m_pLCDBuffered = new CWriteBufferDevice (m_pLCD);
+		m_pLCDBuffered = new CWriteBufferDevice (m_pLCD, 256);
 		assert (m_pLCDBuffered);
 
 		LCDWrite ("\x1B[?25l\x1B""d+");		// cursor off, autopage mode
@@ -202,10 +203,17 @@ bool CUserInterface::Initialize (void)
 
 void CUserInterface::Process (void)
 {
-	if (m_pLCDBuffered)
+	// Limit display updates to avoid glitches on sigle core RPis
+	unsigned nReadTime = CTimer::GetClockTicks ();
+	if (nReadTime - nLastLCDUpdateTime > 50000)
 	{
-		m_pLCDBuffered->Update ();
-	}
+		if (m_pLCDBuffered)
+		{
+			// Limit updates to 16 bytes to avoid glitches on sigle core RPis
+			m_pLCDBuffered->Update (16);
+        }
+        nLastLCDUpdateTime = nReadTime;
+    }
 	if (m_pUIButtons)
 	{
 		m_pUIButtons->Update();

src/userinterface.h

@@ -89,6 +89,7 @@ private:
 	bool m_bSwitchPressed;
 	unsigned m_nRotaryEncoderLastReadTime;
 	int m_nRotaryEncoderCounter=0;
+	unsigned nLastLCDUpdateTime;
 
 	CUIMenu m_Menu;
 };