Pi Firmware: Elk detection was broke - fixed now

Change-Id: I3d3f708f7bf6e62dc0e9e6cb8b0db4c0aacda715

src/osd.c

@@ -79,6 +79,11 @@ static const char *info_names[] = {
    "Calibration Detail"
 };
 
+static const char *machine_names[] = {
+   "Beeb",
+   "Elk"
+};
+
 // =============================================================
 // Feature definitions for OSD
 // =============================================================
@@ -106,7 +111,6 @@ static int info      = INFO_VERSION;
 static int palette   = PALETTE_DEFAULT;
 static int scanlines = 0;
 static int mux       = 0;
-static int elk       = 0;
 static int debug     = 0;
 
 uint32_t *osd_get_palette() {
@@ -239,7 +243,7 @@ static int get_feature(int num) {
    case F_MUX:
       return mux;
    case F_ELK:
-      return elk;
+      return get_elk();
    case F_DEBUG:
       return debug;
    }
@@ -264,8 +268,7 @@ static void set_feature(int num, int value) {
       RPI_SetGpioValue(MUX_PIN, mux);
       break;
    case F_ELK:
-      elk = value;
-      action_elk(value);
+      set_elk(value);
       break;
    case F_DEBUG:
       debug = value;
@@ -275,6 +278,7 @@ static void set_feature(int num, int value) {
 }
 
 static void show_feature(int num) {
+   const char *machine;
    // Read the current value of the specified feature
    int value = get_feature(num);
    // Convert that to a human readable string
@@ -295,10 +299,11 @@ static void show_feature(int num) {
          osd_set(3, 0, message);
          break;
       case INFO_CAL_SUMMARY:
+         machine = machine_names[get_elk()];
          if (clock_error_ppm > 0) {
-            sprintf(message, "Clk Err: %d ppm (Beeb slower than Pi)", clock_error_ppm);
+            sprintf(message, "Clk Err: %d ppm (%s slower than Pi)", clock_error_ppm, machine);
          } else if (clock_error_ppm < 0) {
-            sprintf(message, "Clk Err: %d ppm (Beeb faster than Pi)", -clock_error_ppm);
+            sprintf(message, "Clk Err: %d ppm (%s faster than Pi)", -clock_error_ppm, machine);
          } else {
             sprintf(message, "Clk Err: %d ppm (exact match)", clock_error_ppm);
          }

src/osd.h

@@ -21,7 +21,8 @@ void osd_key(int key);
 uint32_t *osd_get_palette();
 
 void action_calibrate();
-void action_elk(int on);
 void action_scanlines(int on);
+void set_elk(int on);
+int  get_elk();
 
 #endif

src/rgb_to_hdmi.c

@@ -404,11 +404,12 @@ static void cpld_init() {
    cpld->init();
 }
 
-static int test_for_elk(int mode7, int chars_per_line) {
+static int test_for_elk(int elk, int mode7, int chars_per_line) {
 
    // If mode 7, then assume the Beeb
    if (mode7) {
-      return 0;
+      // Leave the setting unchanged
+      return elk;
    }
 
    unsigned int ret;
@@ -416,15 +417,18 @@ static int test_for_elk(int mode7, int chars_per_line) {
 
    // Grab one field
    ret = rgb_to_fb(fb, chars_per_line, pitch, flags);
-
-   // Save a copy
-   memcpy((void *)last, (void *)(fb + ((ret & BIT_LAST_BUFFER) ? SCREEN_HEIGHT * pitch : 0)), SCREEN_HEIGHT * pitch);
+   unsigned char *fb1 = fb + ((ret & BIT_LAST_BUFFER) ? SCREEN_HEIGHT * pitch : 0);
 
    // Grab second field
    ret = rgb_to_fb(fb, chars_per_line, pitch, flags);
-
-   unsigned char *fb1 = last;
    unsigned char *fb2 = fb + ((ret & BIT_LAST_BUFFER) ? SCREEN_HEIGHT * pitch : 0);
+
+   if (fb1 == fb2) {
+      log_warn("test_for_elk() failed, both buffers the same!");
+      // Leave the setting unchanged
+      return elk;
+   }
+
    unsigned int min_diff = INT_MAX;
    unsigned int min_offset = 0;
 
@@ -487,7 +491,7 @@ int *diff_N_frames(int n, int mode7, int elk, int chars_per_line) {
 
    // In mode 0..6, set BIT_CAL_COUNT to 1 (capture 1 field)
    // In mode 7, set BIT_CAL_COUNT to 0 (capture two fields, doesn't matter whether odd-even or even-odd)
-   unsigned int flags = mode7 | BIT_CALIBRATE | (mode7 ? 0 : BIT_CAL_COUNT) | (elk ? BIT_ELK : 0);
+   unsigned int flags = mode7 | BIT_CALIBRATE | (mode7 ? 0 : BIT_CAL_COUNT) | ((elk & !mode7) ? BIT_ELK : 0);
 
 #ifdef INSTRUMENT_CAL
    t = _get_cycle_counter();
@@ -627,7 +631,7 @@ int total_N_frames(int n, int mode7, int elk, int chars_per_line) {
 
    // In mode 0..6, set BIT_CAL_COUNT to 1 (capture 1 field)
    // In mode 7, set BIT_CAL_COUNT to 0 (capture two fields, doesn't matter whether odd-even or even-odd)
-   unsigned int flags = mode7 | BIT_CALIBRATE | (mode7 ? 0 : BIT_CAL_COUNT) | (elk ? BIT_ELK : 0);
+   unsigned int flags = mode7 | BIT_CALIBRATE | (mode7 ? 0 : BIT_CAL_COUNT) | ((elk & !mode7) ? BIT_ELK : 0);
 
    for (int i = 0; i < n; i++) {
       int total = 0;
@@ -692,11 +696,15 @@ void swapBuffer(int buffer) {
 }
 #endif
 
-void action_elk(int on) {
+void set_elk(int on) {
    elk = on;
    clear = BIT_CLEAR;
 }
 
+int get_elk() {
+   return elk;
+}
+
 void action_scanlines(int on) {
    if (on) {
       scanlines = BIT_SCANLINES;
@@ -707,7 +715,8 @@ void action_scanlines(int on) {
 }
 
 void action_calibrate() {
-   elk = test_for_elk(mode7, chars_per_line);
+   // During calibration we do our best to auto-delect an Electron
+   elk = test_for_elk(elk, mode7, chars_per_line);
    log_debug("Elk mode = %d", elk);
    for (int c = 0; c < NUM_CAL_PASSES; c++) {
       cpld->calibrate(elk, chars_per_line);
@@ -746,7 +755,7 @@ void rgb_to_hdmi_main() {
       do {
 
          log_debug("Entering rgb_to_fb");
-         result = rgb_to_fb(fb, chars_per_line, pitch, mode7 | BIT_INITIALIZE | (elk ? BIT_ELK : 0) | clear | scanlines);
+         result = rgb_to_fb(fb, chars_per_line, pitch, mode7 | BIT_INITIALIZE | ((elk & !mode7) ? BIT_ELK : 0) | clear | scanlines);
          log_debug("Leaving rgb_to_fb, result=%04x", result);
          clear = 0;