From 9bc92cbd0be7b1973960e88808feaca26a00aecd Mon Sep 17 00:00:00 2001
From: Felix Domke <tmbinc@elitedvb.net>
Date: Wed, 31 Aug 2005 14:19:02 +0000
Subject: [PATCH]  - fix when not enough framebuffer memory available

---
 lib/gdi/fb.cpp    | 20 ++++++++++++++++----
 lib/gdi/fb.h      |  4 ++++
 lib/gdi/gfbdc.cpp | 37 ++++++++++++++++++++++---------------
 lib/gdi/gfbdc.h   |  3 +++
 main/enigma.cpp   | 10 +++++++++-
 5 files changed, 54 insertions(+), 20 deletions(-)

diff --git a/lib/gdi/fb.cpp b/lib/gdi/fb.cpp
index 4a801bfe..c8fd94be 100644
--- a/lib/gdi/fb.cpp
+++ b/lib/gdi/fb.cpp
@@ -94,12 +94,24 @@ int fbClass::SetMode(unsigned int nxRes, unsigned int nyRes, unsigned int nbpp)
 	screeninfo.width=0;
 	screeninfo.xoffset=screeninfo.yoffset=0;
 	screeninfo.bits_per_pixel=nbpp;
+	
 	if (ioctl(fd, FBIOPUT_VSCREENINFO, &screeninfo)<0)
 	{
-		perror("FBIOPUT_VSCREENINFO");
-		printf("fb failed\n");
-		return -1;
-	}
+		// try single buffering
+		screeninfo.yres_virtual=screeninfo.yres=nyRes;
+		
+		if (ioctl(fd, FBIOPUT_VSCREENINFO, &screeninfo)<0)
+		{
+			perror("FBIOPUT_VSCREENINFO");
+			printf("fb failed\n");
+			return -1;
+		}
+		eDebug(" - double buffering not available.");
+	} else
+		eDebug(" - double buffering available!");
+	
+	m_number_of_pages = screeninfo.yres_virtual / nyRes;
+	
 	if ((screeninfo.xres!=nxRes) && (screeninfo.yres!=nyRes) && (screeninfo.bits_per_pixel!=nbpp))
 	{
 		eDebug("SetMode failed: wanted: %dx%dx%d, got %dx%dx%d",
diff --git a/lib/gdi/fb.h b/lib/gdi/fb.h
index f29c8595..332819fd 100644
--- a/lib/gdi/fb.h
+++ b/lib/gdi/fb.h
@@ -15,11 +15,15 @@ class fbClass
 	static fbClass *instance;
 	int locked;
 	
+	int m_number_of_pages;
 public:
 	unsigned char *lfb;
 	int showConsole(int state);
 	int SetMode(unsigned int xRes, unsigned int yRes, unsigned int bpp);
 	int Available() { return available; }
+	
+	int getNumPages() { return m_number_of_pages; }
+	
 	int setOffset(int off);
 	int waitVSync();
 	unsigned int Stride() { return stride; }
diff --git a/lib/gdi/gfbdc.cpp b/lib/gdi/gfbdc.cpp
index a1f4c981..ee2227cf 100644
--- a/lib/gdi/gfbdc.cpp
+++ b/lib/gdi/gfbdc.cpp
@@ -34,20 +34,24 @@ gFBDC::gFBDC()
 	
 	surface.data_phys = 50*1024*1024; // FIXME
 	
-	surface_back.type = 0;
-	surface_back.x = 720;
-	surface_back.y = 576;
-	surface_back.bpp = 32;
-	surface_back.bypp = 4;
-	surface_back.stride = fb->Stride();
-	surface_back.offset = surface.y;
-
 	int fb_size = surface.stride * surface.y;
 
-	surface_back.data = fb->lfb + fb_size;
-	surface_back.data_phys = surface.data_phys + fb_size;
+	if (fb->getNumPages() > 1)
+	{
+		m_enable_double_buffering = 1;
+		surface_back.type = 0;
+		surface_back.x = 720;
+		surface_back.y = 576;
+		surface_back.bpp = 32;
+		surface_back.bypp = 4;
+		surface_back.stride = fb->Stride();
+		surface_back.offset = surface.y;
+		surface_back.data = fb->lfb + fb_size;
+		surface_back.data_phys = surface.data_phys + fb_size;
 	
-	fb_size *= 2;
+		fb_size *= 2;
+	} else
+		m_enable_double_buffering = 0;
 	
 	eDebug("%dkB available for acceleration surfaces.", (fb->Available() - fb_size)/1024);
 	
@@ -139,11 +143,14 @@ void gFBDC::exec(gOpcode *o)
 	}
 	case gOpcode::flip:
 	{
-		gSurface s(surface);
-		surface = surface_back;
-		surface_back = s;
+		if (m_enable_double_buffering)
+		{
+			gSurface s(surface);
+			surface = surface_back;
+			surface_back = s;
 		
-		fb->setOffset(surface_back.offset);
+			fb->setOffset(surface_back.offset);
+		}
 		break;
 	}
 	case gOpcode::waitVSync:
diff --git a/lib/gdi/gfbdc.h b/lib/gdi/gfbdc.h
index b8ba4c7f..16260fb2 100644
--- a/lib/gdi/gfbdc.h
+++ b/lib/gdi/gfbdc.h
@@ -15,6 +15,7 @@ class gFBDC: public gDC
 	void calcRamp();
 	void setPalette();
 	gSurface surface, surface_back;
+	int m_enable_double_buffering;
 public:
 	void reloadSettings();
 	void setAlpha(int alpha);
@@ -25,6 +26,8 @@ public:
 	int getBrightness() { return brightness; }
 	int getGamma() { return gamma; }
 	
+	int haveDoubleBuffering() { return m_enable_double_buffering; }
+	
 	void saveSettings();
 	
 	gFBDC();
diff --git a/main/enigma.cpp b/main/enigma.cpp
index 16bbcbce..f81a3c28 100644
--- a/main/enigma.cpp
+++ b/main/enigma.cpp
@@ -148,6 +148,8 @@ int main(int argc, char **argv)
 
 	ePython python;
 	eMain main;
+	
+	int double_buffer = 0;
 
 #if 1
 #ifdef SDLDC
@@ -156,13 +158,19 @@ int main(int argc, char **argv)
 #else
 	ePtr<gFBDC> my_dc;
 	gFBDC::getInstance(my_dc);
+	
+	double_buffer = my_dc->haveDoubleBuffering();
 #endif
 
 	fontRenderClass::getInstance()->AddFont(FONTDIR "/arial.ttf", "Arial", 100);
 
 	eWidgetDesktop dsk(eSize(720, 576));
 	
-	dsk.setCompositionMode(eWidgetDesktop::cmBuffered);
+	if (double_buffer)
+	{
+		eDebug(" - double buffering found, enable buffered graphics mode.");
+		dsk.setCompositionMode(eWidgetDesktop::cmBuffered);
+	}
 	
 	wdsk = &dsk;
 
-- 
2.30.2