From bf0861aa0363f55dd95295dca3ccd6ff96acea87 Mon Sep 17 00:00:00 2001
From: Ulrich Sibiller <uli42@gmx.de>
Date: Tue, 2 Jun 2020 21:48:41 +0200
Subject: nxagent: clarify sleep time units

No functional changes, just clarification/explanation of the existing
code.

Fixes ArcticaProject/nx-libs#926
---
 nx-X11/programs/Xserver/hw/nxagent/Args.c     |  2 +-
 nx-X11/programs/Xserver/hw/nxagent/Handlers.c | 16 ++++++++--------
 nx-X11/programs/Xserver/hw/nxagent/Image.c    | 14 ++++++++++++--
 nx-X11/programs/Xserver/hw/nxagent/Options.c  |  2 +-
 nx-X11/programs/Xserver/hw/nxagent/Options.h  |  8 +++++---
 5 files changed, 27 insertions(+), 15 deletions(-)

diff --git a/nx-X11/programs/Xserver/hw/nxagent/Args.c b/nx-X11/programs/Xserver/hw/nxagent/Args.c
index 39fa6c5e2..1ae1b570b 100644
--- a/nx-X11/programs/Xserver/hw/nxagent/Args.c
+++ b/nx-X11/programs/Xserver/hw/nxagent/Args.c
@@ -1365,7 +1365,7 @@ static void nxagentParseSingleOption(char *name, char *value)
                       validateString(value), validateString(name), sleep_parse);
     }
 
-    nxagentChangeOption(SleepTime, sleep_parse);
+    nxagentChangeOption(SleepTimeMillis, sleep_parse);
     return;
   }
   else if (!strcmp(name, "tolerancechecks"))
diff --git a/nx-X11/programs/Xserver/hw/nxagent/Handlers.c b/nx-X11/programs/Xserver/hw/nxagent/Handlers.c
index 411dfe933..9f0a3c9d9 100644
--- a/nx-X11/programs/Xserver/hw/nxagent/Handlers.c
+++ b/nx-X11/programs/Xserver/hw/nxagent/Handlers.c
@@ -235,18 +235,18 @@ void nxagentBlockHandler(void * data, struct timeval **timeout, void * mask)
    * display.
    */
 
-  if (NXDisplayError(nxagentDisplay) == 1 && nxagentShadowCounter == 0 && nxagentOption(SleepTime) > 0)
+  if (NXDisplayError(nxagentDisplay) == 1 && nxagentShadowCounter == 0 && nxagentOption(SleepTimeMillis) > 0)
   {
 #ifdef TEST
     fprintf(stderr, "nxagentBlockHandler: sleeping for %d milliseconds for slowdown.\n",
-                    nxagentOption(SleepTime));
+                    nxagentOption(SleepTimeMillis));
 #endif
-    usleep(nxagentOption(SleepTime) * 1000);
+    usleep(nxagentOption(SleepTimeMillis) * 1000);
 
     now = GetTimeInMillis();
   }
 #ifdef TEST
-  else if (0 == nxagentOption(SleepTime)) {
+  else if (0 == nxagentOption(SleepTimeMillis)) {
     fprintf(stderr, "nxagentBlockHandler: not sleeping for slowdown.\n");
   }
 #endif
@@ -708,16 +708,16 @@ void nxagentShadowBlockHandler(void * data, struct timeval **timeout, void * mas
     nxagentHandleConnectionChanges();
   }
 
-  if (nxagentSessionState == SESSION_DOWN && nxagentOption(SleepTime) > 0)
+  if (nxagentSessionState == SESSION_DOWN && nxagentOption(SleepTimeMillis) > 0)
   {
     #ifdef TEST
     fprintf(stderr, "nxagentShadowBlockHandler: sleeping for %d milliseconds for slowdown.\n",
-                    nxagentOption(SleepTime));
+                    nxagentOption(SleepTimeMillis));
     #endif
-    usleep(nxagentOption(SleepTime) * 1000);
+    usleep(nxagentOption(SleepTimeMillis) * 1000);
   }
   #ifdef TEST
-  else if (0 == nxagentOption(SleepTime)) {
+  else if (0 == nxagentOption(SleepTimeMillis)) {
     fprintf(stderr, "nxagentShadowBlockHandler: not sleeping for slowdown.\n");
   }
   #endif
diff --git a/nx-X11/programs/Xserver/hw/nxagent/Image.c b/nx-X11/programs/Xserver/hw/nxagent/Image.c
index 9369aeb1e..db174a9de 100644
--- a/nx-X11/programs/Xserver/hw/nxagent/Image.c
+++ b/nx-X11/programs/Xserver/hw/nxagent/Image.c
@@ -492,9 +492,19 @@ void nxagentPutImage(DrawablePtr pDrawable, GCPtr pGC, int depth,
 
   if (nxagentShadowCounter == 0 &&
           NXDisplayError(nxagentDisplay) == 1 &&
-              nxagentOption(SleepTime) > 0)
+              nxagentOption(SleepTimeMillis) > 0)
   {
-    int us = nxagentOption(SleepTime) * 4 * (length / 1024);
+    /*
+     * The original NX code had 250us (microseconds) * length/1024
+     * here and 50ms (milliseconds) elsewhere. Later ONE combined
+     * configurable sleep parameter was introduced, having a default
+     * of 50ms (that's milliseconds, not microseconds!), which is
+     * factor 200. For unknown reasons the factor was changed to 250
+     * at the same time.  Ensure the value is somewhere between 10ms
+     * and 1s.
+     */
+
+    int us = nxagentOption(SleepTimeMillis) * 1000 * (length / 1024) / 250;
 
     us = (us < 10000 ? 10000 : (us > 1000000 ? 1000000 : us));
 
diff --git a/nx-X11/programs/Xserver/hw/nxagent/Options.c b/nx-X11/programs/Xserver/hw/nxagent/Options.c
index 4d5fa3e16..0da504f06 100644
--- a/nx-X11/programs/Xserver/hw/nxagent/Options.c
+++ b/nx-X11/programs/Xserver/hw/nxagent/Options.c
@@ -157,7 +157,7 @@ void nxagentInitOptions(void)
 
   nxagentOptions.Xinerama = 1;
 
-  nxagentOptions.SleepTime = DEFAULT_SLEEP_TIME;
+  nxagentOptions.SleepTimeMillis = DEFAULT_SLEEP_TIME_MILLIS;
 
   nxagentOptions.ReconnectTolerance = DEFAULT_TOLERANCE;
 
diff --git a/nx-X11/programs/Xserver/hw/nxagent/Options.h b/nx-X11/programs/Xserver/hw/nxagent/Options.h
index 166508ac3..e56860f04 100644
--- a/nx-X11/programs/Xserver/hw/nxagent/Options.h
+++ b/nx-X11/programs/Xserver/hw/nxagent/Options.h
@@ -36,7 +36,9 @@
 
 #define UNDEFINED -1
 #define COPY_UNLIMITED -1
-#define DEFAULT_SLEEP_TIME 50
+
+/* in milliseconds */
+#define DEFAULT_SLEEP_TIME_MILLIS 50
 
 extern unsigned int nxagentPrintGeometryFlags;
 
@@ -366,9 +368,9 @@ typedef struct _AgentOptions
   int Xinerama;
 
   /*
-   * Sleep delay in microseconds.
+   * Sleep delay in milliseconds.
    */
-  unsigned int SleepTime;
+  unsigned int SleepTimeMillis;
 
   /*
    * Tolerance - tightens or loosens reconnect checks.
-- 
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