Fix HDMI not working on bootup with some SD cards

src/geometry.c

@@ -640,7 +640,7 @@ void geometry_get_fb_params(capture_info_t *capinfo) {
     capinfo->height &= 0xfffffffe;
 
     if (capinfo->chars_per_line > ((capinfo->width + 7) >> 3)) {
-       //log_info("Clipping capture width: %d, %d, %d", capinfo->width, capinfo->width >> 3, capinfo->nlines); 
+       //log_info("Clipping capture width: %d, %d, %d", capinfo->width, capinfo->width >> 3, capinfo->nlines);
        capinfo->chars_per_line = ((capinfo->width + 7) >> 3);
     }
 
@@ -690,9 +690,17 @@ int get_vaspect() {
 }
 
 int get_hdisplay() {
+#if defined(RPI4)
+    int h_size = 1920;
+#else
     int h_size = (*PIXELVALVE2_HORZB) & 0xFFFF;
-    //workaround for 640x480 and 800x480 @50Hz using double rate clock so width gets doubled
     int v_size = (*PIXELVALVE2_VERTB) & 0xFFFF;
+    if (h_size < 640 || h_size > 8192 || v_size < 480 || v_size > 4096) {
+          log_info("HDMI readback of screen size invalid (%dx%d) - rebooting", h_size, v_size);
+          delay_in_arm_cycles_cpu_adjust(1000000000);
+          reboot();
+    }
+    //workaround for 640x480 and 800x480 @50Hz using double rate clock so width gets doubled
     if (v_size == 480 && h_size == 1280) {
         h_size = 640;
     } else {
@@ -700,16 +708,19 @@ int get_hdisplay() {
             h_size = 800;
         }
     }
-    if (h_size < 320) h_size = 1920;
+#endif
     return h_size;
 }
+
 int get_vdisplay() {
+#if defined(RPI4)
+    int v_size = 1080;
+#else
     int v_size = (*PIXELVALVE2_VERTB) & 0xFFFF;
-    if (v_size < 200) v_size = 1080;
+#endif
     return v_size;
 }
 
-
 void geometry_get_clk_params(clk_info_t *clkinfo) {
    clkinfo->clock            = geometry->clock;
    clkinfo->line_len         = geometry->line_len;

src/rgb_to_hdmi.c

@@ -420,14 +420,14 @@ static int last_height = -1;
 
    // FIXME: A small delay (like the log) is neccessary here
    // or the RPI_PropertyGet seems to return garbage
-   delay_in_arm_cycles_cpu_adjust(8000000);
+   delay_in_arm_cycles_cpu_adjust(4000000);
    log_info("Initialised Framebuffer");
 
    if ((mp = RPI_PropertyGet(TAG_GET_PHYSICAL_SIZE))) {
       int width = mp->data.buffer_32[0];
       int height = mp->data.buffer_32[1];
-      log_info("Size: %dx%d ", width, height);
-      if (width == 1920 && height == 8192) {
+      log_info("Size: %dx%d (requested %dx%d)", width, height, capinfo->width, capinfo->height);
+      if (width != capinfo->width || height != capinfo->height) {
           log_info("Invalid frame buffer dimensions - maybe HDMI not connected - rebooting");
           delay_in_arm_cycles_cpu_adjust(1000000000);
           reboot();
@@ -1232,8 +1232,6 @@ static void init_hardware() {
    // Initialize the cpld after the gpclk generator has been started
    cpld_init();
 
-   delay_in_arm_cycles_cpu_adjust(500000000);
-
    // Initialize the On-Screen Display
    osd_init();
 
@@ -2166,6 +2164,8 @@ void setup_profile(int profile_changed) {
     cpld->set_mode(mode7);
     log_debug("Done loading sample points");
 
+    log_info("Detected screen size = %dx%d",get_hdisplay(), get_vdisplay());
+
     geometry_get_fb_params(capinfo);
 
     if (autoswitch == AUTOSWITCH_MODE7) {