From 488e7478869efae33a5fdc1c9f1d5465c4120d8d Mon Sep 17 00:00:00 2001
From: Mark Pizzolato <mark@infocomm.com>
Date: Wed, 30 Mar 2016 09:59:09 -0700
Subject: [PATCH] PDP11, VAX: Assure that DMA output to non-connected lines
 completes normally

Also make all scheduled timing behaviors consistent and not performed by
the input polling unit which may have different scheduling characteristics
to reflect input speed rate limiting.
---
 PDP11/pdp11_vh.c | 35 ++++++++++++++++-------------------
 1 file changed, 16 insertions(+), 19 deletions(-)

diff --git a/PDP11/pdp11_vh.c b/PDP11/pdp11_vh.c
index f6c2810e..5e083935 100644
--- a/PDP11/pdp11_vh.c
+++ b/PDP11/pdp11_vh.c
@@ -927,7 +927,8 @@ static t_stat vh_wr (   int32   ldata,
                 data &= ~CSR_MASTER_RESET;
             if (vh == 0) /* Only start unit service on the first unit.  Units are polled there */
                 sim_clock_coschedule (&vh_unit[0], tmxr_poll);
-            sim_activate_after (&vh_unit[vh_dev.numunits-1], 120000);  /* 120 milliseconds */
+            vh_mcount[vh] = MS2SIMH (1200); /* 1.2 seconds */
+            sim_clock_coschedule (&vh_unit[vh_dev.numunits-1], tmxr_poll);
         }
         if ((data & CSR_RXIE) == 0)
             vh_clr_rxint (vh);
@@ -1211,7 +1212,7 @@ static void doDMA ( int32   vh,
         lp->tbuf1 = pa & 0177777;
         lp->tbuf2 = (lp->tbuf2 & ~TB2_M_TBUFFAD) |
                 ((pa >> 16) & TB2_M_TBUFFAD);
-        if (lp->tbuffct == 0) {
+        if ((lp->tbuffct == 0) || (!lp->tmln->conn)) {
             lp->tbuf2 &= ~TB2_TX_DMA_START;
             q_tx_report (vh, status);
         }
@@ -1222,24 +1223,30 @@ static void doDMA ( int32   vh,
 
 static t_stat vh_timersvc (  UNIT    *uptr   )
 {
-    int32   vh, again;
+    int32   vh;
 
     sim_debug(DBG_TRC, find_dev_from_unit(uptr), "vh_timersvc()\n");
 
+    /* scan all DHU-mode muxes for RX FIFO timeout */
+    for (vh = 0; vh < vh_desc.lines/VH_LINES; vh++) {
+        if (vh_unit[vh].flags & UNIT_MODEDHU) {
+            if (vh_timeo[vh] && (vh_csr[vh] & CSR_RXIE)) {
+                vh_timeo[vh] -= 1;
+                if ((vh_timeo[vh] == 0) && rbuf_idx[vh])
+                    vh_set_rxint (vh);
+            }
+        }
+    }
     /* scan all muxes for countdown reset */
-    again = 0;
     for (vh = 0; vh < vh_desc.lines/VH_LINES; vh++) {
         if (vh_csr[vh] & CSR_MASTER_RESET) {
-            if (vh_mcount[vh] != 0) {
+            if (vh_mcount[vh] != 0)
                 vh_mcount[vh] -= 1;
-                ++again;
-                }
             else
                 vh_clear (vh, FALSE);
         }
     }
-    if (again)
-        sim_clock_coschedule (uptr, tmxr_poll); /* requeue ourselves */
+    sim_clock_coschedule (uptr, tmxr_poll); /* requeue ourselves */
     return (SCPE_OK);
 }
 
@@ -1276,16 +1283,6 @@ static t_stat vh_svc (  UNIT    *uptr   )
     for (vh = 0; vh < vh_desc.lines/VH_LINES; vh++)
         vh_getc (vh);
     tmxr_poll_tx (&vh_desc);
-    /* scan all DHU-mode muxes for RX FIFO timeout */
-    for (vh = 0; vh < vh_desc.lines/VH_LINES; vh++) {
-        if (vh_unit[vh].flags & UNIT_MODEDHU) {
-            if (vh_timeo[vh] && (vh_csr[vh] & CSR_RXIE)) {
-                vh_timeo[vh] -= 1;
-                if ((vh_timeo[vh] == 0) && rbuf_idx[vh])
-                    vh_set_rxint (vh);
-            }
-        }
-    }
     sim_clock_coschedule (uptr, tmxr_poll); /* requeue ourselves */
     return (SCPE_OK);
 }