From 679ef1451d645b31dfaed9f3e71e8cab81b2178f Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Thu, 23 Jan 1992 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1992-01-23

---
 port/devkprof.c |  2 +-
 power/devhs.c   | 19 ++++++++++++++++---
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/port/devkprof.c b/port/devkprof.c
index 2d8eb5d3543e68807d1f4d381f4c9516b248fc3d..82191a187833c6afd63896f273d2555f6b6b45d5 100644
--- a/port/devkprof.c
+++ b/port/devkprof.c
@@ -195,6 +195,6 @@ kproftimer(ulong pc)
 		pc -= kprof.minpc;
 		pc >>= LRES;
 		kprof.buf[pc] += TK2MS(1);
-	} else
+	}else
 		kprof.buf[1] += TK2MS(1);
 }
diff --git a/power/devhs.c b/power/devhs.c
index b9a3a3075faf0a0f08f95076a03c7a59b793990c..8598f9d78f00f13579610b30ccae095a69d8ca2c 100644
--- a/power/devhs.c
+++ b/power/devhs.c
@@ -18,6 +18,8 @@ enum {
 	Nhsvme=		1,
 };
 
+#define NOW (MACHP(0)->ticks*MS2HZ)
+
 /*
  *  hsvme datakit board
  */
@@ -44,6 +46,7 @@ struct Hsvme {
 	Queue	*rq;		/* read queue */
 	uchar	buf[1024];	/* bytes being collected */
 	uchar	*wptr;		/* pointer into buf */
+	ulong	time;		/* time byte in buf[0] arrived */
 	int	kstarted;	/* true if kernel process started */
 	int	started;
 
@@ -458,6 +461,7 @@ upstream(Hsvme *hp, unsigned int ctl)
 	bp->flags |= S_DELIM;
 	PUTNEXT(hp->rq, bp);
 	hp->wptr = hp->buf;
+	hp->time = 0;
 }
 
 /*
@@ -526,20 +530,29 @@ hsvmekproc(void *arg)
 				/*
 				 *  data byte, put in local buffer
 				 */
+				if(hp->time == 0)
+					hp->time = NOW + 100;
 				*hp->wptr++ = c;
 				if(hp->wptr == &hp->buf[sizeof hp->buf])
 					upstream(hp, 0);
 			}
 		}
+		if(hp->time && NOW >= hp->time)
+			upstream(hp, 0);
 		USED(locked);
 		qunlock(hp);
 		locked = 0;
 
 		/*
-		 *  sleep if input fifo empty
+		 *  Sleep if input fifo empty. Make sure we don't hold onto
+		 *  any byte for more tha 1/10 second.
 		 */
-		if(!notempty(addr))
-			sleep(&hp->kr, notempty, addr);
+		if(!(addr->csr & REF)){
+			if(hp->wptr == hp->buf)
+				sleep(&hp->kr, notempty, addr);
+			else
+				tsleep(&hp->kr, notempty, addr, 100);
+		}
 	}
 }