Pi Firmware: made SHOW_VSYNC independent of POLL_VSYNC

Change-Id: I020643ac24d7bc6345bf371a6e39cc9114d9d573

src/defs.h

@@ -32,20 +32,24 @@
 #define BIT_PROBE        0x02
 #define BIT_CALIBRATE    0x04
 #define BIT_CAL_COUNT    0x08
-#define BIT_INITIALIZE   0x10
+#define BIT_VSYNC_SEEN   0x10
 #define BIT_ELK          0x20
 #define BIT_SCANLINES    0x40
 #define BIT_FIELD_TYPE   0x80
 #define BIT_CLEAR        0x100
 #define BIT_VSYNC        0x200
+#define BIT_INITIALIZE   0x400
+
+// Note, due to a hack, bits 16, 19 and 26 are unavailale
+// as the are used for switch change detection
 
-#define OFFSET_NBUFFERS    10
 #define OFFSET_LAST_BUFFER 12
 #define OFFSET_CURR_BUFFER 14
+#define OFFSET_NBUFFERS    17
 
-#define MASK_NBUFFERS    (3 << OFFSET_NBUFFERS)
 #define MASK_LAST_BUFFER (3 << OFFSET_LAST_BUFFER)
 #define MASK_CURR_BUFFER (3 << OFFSET_CURR_BUFFER)
+#define MASK_NBUFFERS    (3 << OFFSET_NBUFFERS)
 
 // R0 return value bits
 #define RET_SW1          0x02

src/rgb_to_fb.S

@@ -17,9 +17,9 @@
 
 .macro SHOW_VSYNC
         mov    r7, #0
-        tst    r3, #BIT_VSYNC
+        tst    r3, #(BIT_VSYNC)
         beq    novsync\@
-        tst    r3, #(BIT_MODE7 | BIT_PROBE)
+        tst    r3, #(BIT_MODE7 | BIT_PROBE | BIT_VSYNC_SEEN)
         bne    novsync\@
         ldr    r0, =INTPEND2
         ldr    r0, [r0]
@@ -34,6 +34,7 @@
         orr    r7, #0x00110000
         orr    r7, #0x00001100
         orr    r7, #0x00000011
+        orr    r3, r3, #BIT_VSYNC_SEEN
 novsync\@:
 .endm
 
@@ -388,6 +389,9 @@ skip_line_loop:
 
         // Process active lines
         ldr    r5, =NUM_ACTIVE
+
+        // Clear the vsync-seen flag
+        bic    r3, r3, #BIT_VSYNC_SEEN
 process_line_loop:
 
         SHOW_VSYNC