coco3: dw: maintain faster polling for short while after a putc.

From Michael Furman: improves interactivity on clients.

diff --git a/Kernel/platform-coco3/ttydw.c b/Kernel/platform-coco3/ttydw.c
index e899912..ff1df15 100644 (file)
--- a/Kernel/platform-coco3/ttydw.c
+++ b/Kernel/platform-coco3/ttydw.c
@@ -117,6 +117,11 @@ struct dw_in dwtab[ DW_VSER_NUM + DW_VWIN_NUM ];
 
 int wait=MAX_WAIT;
 
+/* How many vsync ticks to wait until polling again after a FastWrite */
+#define FASTWRITE_WAIT     1
+#define FASTWRITE_WAIT_COUNT  8
+int fastWriteWait = 0;
+
 /* Number of ports open. IF zero then polling routine
    will not poll */
 int open_ports=0;
@@ -162,6 +167,9 @@ void dw_putc( uint8_t minor, unsigned char c ){
        buf[0]=DW_FASTWRITE | dw_port( minor ) ;
        buf[1]=c;
        dw_transaction( buf, 2, NULL, 0, 0 );
+       /* set wait and fastWriteWait for interactive performance */
+       wait=FASTWRITE_WAIT;
+       fastWriteWait=FASTWRITE_WAIT_COUNT;
 }
 
 
@@ -200,7 +208,17 @@ int qfree( uint8_t minor ){
        return q->q_size - q->q_count;
 }
 
-
+/* Sets the wait time to v if not in fast wait */
+static inline void setWait( int v )
+{
+       if (fastWriteWait) {
+               fastWriteWait--;
+               wait = FASTWRITE_WAIT;
+       } else {
+               wait = v;
+       }
+       return;
+}
 
 /* Poll and add chars (if any) to input q
  */
@@ -217,13 +235,14 @@ void dw_vpoll( ){
                dw_transaction( buf, 1, buf, 2, 0 );
                /* nothing waiting ? */
                if( ! (buf[0] & 0x7f) ) {
-                       wait=MAX_WAIT;
+                       setWait(MAX_WAIT);
                        break;
                }
                /* VSER Channel single datum */
                if( buf[0]<16 ){
                        int minor=dw_minor( buf[0] - 1 );
                        tty_inproc( minor, buf[1] );
+                       fastWriteWait = 0;
                        continue;
                }
                /* VSER Channel closed? */
@@ -249,7 +268,7 @@ void dw_vpoll( ){
                        min=mini( buf[1], qfree( minor ) );
                        b[2]=min;
                        if( !min ){
-                               wait = MAX_WAIT;
+                               setWait(MAX_WAIT);
                                break;
                        }
                        dw_transaction( b,3,tbuf, min, 0 );
@@ -257,6 +276,7 @@ void dw_vpoll( ){
                                tty_inproc( minor, tbuf[i] );
                        }
                        wait = 16 - (min >> 4);
+                       fastWriteWait = 0;
                        break;
                }
                /* VWIN channel single datum */