cleanup
- print ^U \n when user kills line
- fix prflush
- remove swap junk

Reference: /n/atom/patch/applied2013/consctlu
Date: Sun Dec 29 22:15:29 CET 2013
Signed-off-by: quanstro@quanstro.net

--- /sys/src/nix/port/devcons.c	Sun Dec 29 22:14:44 2013
+++ /sys/src/nix/port/devcons.c	Sun Dec 29 22:14:46 2013
@@ -79,7 +79,6 @@
 static	char	*sysname;
 static	vlong	fasthz;
 
-static void	seedrand(void);
 static int	readtime(ulong, char*, int);
 static int	readbintime(char*, int);
 static int	writetime(char*, int);
@@ -212,15 +211,21 @@
 	return 0;
 }
 
+/* must be safe to call from any context */
 void
 prflush(void)
 {
-	ulong now;
+	uvlong now;
 
-	now = m->ticks;
-	while(consactive())
-		if(m->ticks - now >= HZ)
+	now = µs();
+	while(consactive()){
+		if(µs() - now >= 1000000)
 			break;
+		if(up != nil && islo())
+			tsleep(&up->sleep, return0, nil, 1);
+		else
+			delay(1);
+	}
 }
 
 /*
@@ -291,10 +296,8 @@
 }
 
 /*
- *   Print a string on the console.  Convert \n to \r\n for serial
- *   line consoles.  Locking of the queues is left up to the screen
- *   or uart code.  Multi-line messages to serial consoles may get
- *   interspersed with other messages.
+ * Print a string on the consoles.  Convert \n to \r\n if necessary.
+ * Multi-line messages may be interspersed.
  */
 static void
 putstrn0(char *str, int n, int usewrite)
@@ -821,7 +824,6 @@
 	long offset;
 	extern int schedsteals, scheddonates;
 
-
 	if(n <= 0)
 		return n;
 
@@ -857,6 +859,7 @@
 					kbd.x = i;
 					break;
 				case 0x15:	/* ^U */
+					print("\b^U\n");
 					kbd.x = 0;
 					break;
 				case '\n':
@@ -1149,7 +1152,6 @@
 	case Qsysstat:
 		for(i = 0; i < MACHMAX; i++)
 			if((mp = sys->machptr[i]) != nil && mp->online != 0){
-				mp = MACHP(i);
 				mp->cs = 0;
 				mp->intr = 0;
 				mp->syscall = 0;
@@ -1160,18 +1162,7 @@
 		break;
 
 	case Qswap:
-		if(n >= sizeof buf)
-			error(Egreg);
-		memmove(buf, va, n);	/* so we can NUL-terminate */
-		buf[n] = 0;
-		if(!iseve())
-			error(Eperm);
-		if(buf[0]<'0' || '9'<buf[0])
-			error(Ebadarg);
-		if(strncmp(buf, "start", 5) == 0){
-			print("request to start pager ignored\n");
-			break;
-		}
+		error("swap not supported");
 		break;
 
 	case Qsysname: