Bug#454523: xscreensaver hangs if machine is suspended during fade-out/fade-in

[Jamie Zawinski]

Thanks!  I think this is a bit simpler, though: does this patch work  
for you?

diff -u -r1.32 fade.c
--- fade.c      9 Jul 2005 03:11:42 -0000       1.32
+++ fade.c      26 Jan 2008 23:10:18 -0000
@@ -157,6 +157,28 @@
 }
 
 
+static void
+sleep_from (struct timeval *now, struct timeval *then, long usecs_per_step)
+{
+  /* If several seconds have passed, the machine must have been asleep
+     or thrashing or something.  Don't sleep in that case, to avoid
+     overflowing and sleeping for an unconscionably long time.  This
+     function should only be sleeping for very short periods.
+   */
+  if (now->tv_sec - then->tv_sec < 5)
+    {
+      long diff = (((now->tv_sec - then->tv_sec) * 1000000) +
+                   now->tv_usec - then->tv_usec);
+      if (usecs_per_step > diff)
+        usleep (usecs_per_step - diff);
+    }
+
+  then->tv_sec  = now->tv_sec;
+  then->tv_usec = now->tv_usec;
+}
+
+
+
 /* The business with `cmaps_per_screen' is to fake out the SGI 8-bit video
    hardware, which is capable of installing multiple (4) colormaps
    simultaneously.  We have to install multiple copies of the same set of
@@ -329,14 +351,7 @@
 
       /* If we haven't already used up our alotted time, sleep to avoid
         changing the colormap too fast. */
-      {
-       long diff = (((now.tv_sec - then.tv_sec) * 1000000) +
-                    now.tv_usec - then.tv_usec);
-       then.tv_sec = now.tv_sec;
-       then.tv_usec = now.tv_usec;
-       if (usecs_per_step > diff)
-         usleep (usecs_per_step - diff);
-      }
+      sleep_from (&now, &then, usecs_per_step);
     }
 
  DONE:
@@ -530,14 +545,7 @@
 
          /* If we haven't already used up our alotted time, sleep to avoid
             changing the colormap too fast. */
-         {
-           long diff = (((now.tv_sec - then.tv_sec) * 1000000) +
-                        now.tv_usec - then.tv_usec);
-           then.tv_sec = now.tv_sec;
-           then.tv_usec = now.tv_usec;
-           if (usecs_per_step > diff)
-             usleep (usecs_per_step - diff);
-         }
+          sleep_from (&now, &then, usecs_per_step);
        }
     }
   
@@ -757,14 +765,7 @@
 
          /* If we haven't already used up our alotted time, sleep to avoid
             changing the colormap too fast. */
-         {
-           long diff = (((now.tv_sec - then.tv_sec) * 1000000) +
-                        now.tv_usec - then.tv_usec);
-           then.tv_sec = now.tv_sec;
-           then.tv_usec = now.tv_usec;
-           if (usecs_per_step > diff)
-             usleep (usecs_per_step - diff);
-         }
+          sleep_from (&now, &then, usecs_per_step);
        }
     }