diff --git a/dlls/ntdll/debugtools.c b/dlls/ntdll/debugtools.c
index 9c3add4bfed..1e4a3a1aba1 100644
--- a/dlls/ntdll/debugtools.c
+++ b/dlls/ntdll/debugtools.c
@@ -43,6 +43,12 @@ WINE_DECLARE_DEBUG_CHANNEL(timestamp);
 
 static BOOL init_done;
 static struct debug_info initial_info;  /* debug info for initial thread */
+static unsigned char default_flags = (1 << __WINE_DBCL_ERR) | (1 << __WINE_DBCL_FIXME);
+static int nb_debug_options = -1;
+static int options_size;
+static struct __wine_debug_channel *debug_options;
+
+static const char * const debug_classes[] = { "fixme", "err", "warn", "trace" };
 
 /* get the debug info pointer for the current thread */
 static inline struct debug_info *get_info(void)
@@ -88,6 +94,153 @@ static int append_output( struct debug_info *info, const char *str, size_t len )
     return len;
 }
 
+/* add a new debug option at the end of the option list */
+static void add_option( const char *name, unsigned char set, unsigned char clear )
+{
+    int min = 0, max = nb_debug_options - 1, pos, res;
+
+    if (!name[0])  /* "all" option */
+    {
+        default_flags = (default_flags & ~clear) | set;
+        return;
+    }
+    if (strlen(name) >= sizeof(debug_options[0].name)) return;
+
+    while (min <= max)
+    {
+        pos = (min + max) / 2;
+        res = strcmp( name, debug_options[pos].name );
+        if (!res)
+        {
+            debug_options[pos].flags = (debug_options[pos].flags & ~clear) | set;
+            return;
+        }
+        if (res < 0) max = pos - 1;
+        else min = pos + 1;
+    }
+    if (nb_debug_options >= options_size)
+    {
+        options_size = max( options_size * 2, 16 );
+        debug_options = realloc( debug_options, options_size * sizeof(debug_options[0]) );
+    }
+
+    pos = min;
+    if (pos < nb_debug_options) memmove( &debug_options[pos + 1], &debug_options[pos],
+                                         (nb_debug_options - pos) * sizeof(debug_options[0]) );
+    strcpy( debug_options[pos].name, name );
+    debug_options[pos].flags = (default_flags & ~clear) | set;
+    nb_debug_options++;
+}
+
+/* parse a set of debugging option specifications and add them to the option list */
+static void parse_options( const char *str )
+{
+    char *opt, *next, *options;
+    unsigned int i;
+
+    if (!(options = strdup(str))) return;
+    for (opt = options; opt; opt = next)
+    {
+        const char *p;
+        unsigned char set = 0, clear = 0;
+
+        if ((next = strchr( opt, ',' ))) *next++ = 0;
+
+        p = opt + strcspn( opt, "+-" );
+        if (!p[0]) p = opt;  /* assume it's a debug channel name */
+
+        if (p > opt)
+        {
+            for (i = 0; i < ARRAY_SIZE(debug_classes); i++)
+            {
+                int len = strlen(debug_classes[i]);
+                if (len != (p - opt)) continue;
+                if (!memcmp( opt, debug_classes[i], len ))  /* found it */
+                {
+                    if (*p == '+') set |= 1 << i;
+                    else clear |= 1 << i;
+                    break;
+                }
+            }
+            if (i == ARRAY_SIZE(debug_classes)) /* bad class name, skip it */
+                continue;
+        }
+        else
+        {
+            if (*p == '-') clear = ~0;
+            else set = ~0;
+        }
+        if (*p == '+' || *p == '-') p++;
+        if (!p[0]) continue;
+
+        if (!strcmp( p, "all" ))
+            default_flags = (default_flags & ~clear) | set;
+        else
+            add_option( p, set, clear );
+    }
+    free( options );
+}
+
+/* print the usage message */
+static void debug_usage(void)
+{
+    static const char usage[] =
+        "Syntax of the WINEDEBUG variable:\n"
+        "  WINEDEBUG=[class]+xxx,[class]-yyy,...\n\n"
+        "Example: WINEDEBUG=+relay,warn-heap\n"
+        "    turns on relay traces, disable heap warnings\n"
+        "Available message classes: err, warn, fixme, trace\n";
+    write( 2, usage, sizeof(usage) - 1 );
+    exit(1);
+}
+
+/* initialize all options at startup */
+static void init_options(void)
+{
+    char *wine_debug = getenv("WINEDEBUG");
+    struct stat st1, st2;
+
+    nb_debug_options = 0;
+
+    /* check for stderr pointing to /dev/null */
+    if (!fstat( 2, &st1 ) && S_ISCHR(st1.st_mode) &&
+        !stat( "/dev/null", &st2 ) && S_ISCHR(st2.st_mode) &&
+        st1.st_rdev == st2.st_rdev)
+    {
+        default_flags = 0;
+        return;
+    }
+    if (!wine_debug) return;
+    if (!strcmp( wine_debug, "help" )) debug_usage();
+    parse_options( wine_debug );
+}
+
+/***********************************************************************
+ *		__wine_dbg_get_channel_flags  (NTDLL.@)
+ *
+ * Get the flags to use for a given channel, possibly setting them too in case of lazy init
+ */
+unsigned char __cdecl __wine_dbg_get_channel_flags( struct __wine_debug_channel *channel )
+{
+    int min, max, pos, res;
+
+    if (nb_debug_options == -1) init_options();
+
+    min = 0;
+    max = nb_debug_options - 1;
+    while (min <= max)
+    {
+        pos = (min + max) / 2;
+        res = strcmp( channel->name, debug_options[pos].name );
+        if (!res) return debug_options[pos].flags;
+        if (res < 0) max = pos - 1;
+        else min = pos + 1;
+    }
+    /* no option for this channel */
+    if (channel->flags & (1 << __WINE_DBCL_INIT)) channel->flags = default_flags;
+    return default_flags;
+}
+
 /***********************************************************************
  *		__wine_dbg_strdup  (NTDLL.@)
  */
diff --git a/dlls/ntdll/ntdll.spec b/dlls/ntdll/ntdll.spec
index 98991adcee3..b608ab9ac87 100644
--- a/dlls/ntdll/ntdll.spec
+++ b/dlls/ntdll/ntdll.spec
@@ -1506,6 +1506,7 @@
 @ cdecl __wine_make_process_system()
 
 # Debugging
+@ cdecl -norelay __wine_dbg_get_channel_flags(ptr)
 @ cdecl -norelay __wine_dbg_output(str)
 @ cdecl -norelay __wine_dbg_strdup(str)
 
diff --git a/include/wine/debug.h b/include/wine/debug.h
index 2412c2b922a..416b6c8ff83 100644
--- a/include/wine/debug.h
+++ b/include/wine/debug.h
@@ -156,9 +156,7 @@ struct __wine_debug_functions
                      const char *function, const char *format, va_list args );
 };
 
-extern unsigned char __wine_dbg_get_channel_flags( struct __wine_debug_channel *channel );
-extern int __wine_dbg_set_channel_flags( struct __wine_debug_channel *channel,
-                                         unsigned char set, unsigned char clear );
+extern unsigned char __cdecl __wine_dbg_get_channel_flags( struct __wine_debug_channel *channel );
 extern void __wine_dbg_set_functions( const struct __wine_debug_functions *new_funcs,
                                       struct __wine_debug_functions *old_funcs, size_t size );
 extern const char * __cdecl __wine_dbg_strdup( const char *str );
diff --git a/libs/wine/debug.c b/libs/wine/debug.c
index 2d56b015702..b9c7e0bbe68 100644
--- a/libs/wine/debug.c
+++ b/libs/wine/debug.c
@@ -30,6 +30,7 @@
 # include <sys/stat.h>
 #endif
 
+#define __wine_dbg_get_channel_flags __wine_dbg_get_channel_flags_inline
 #define wine_dbg_sprintf wine_dbg_sprintf_inline
 #define wine_dbg_printf wine_dbg_printf_inline
 #define wine_dbgstr_an wine_dbgstr_an_inline
@@ -61,6 +62,7 @@ static int cmp_name( const void *p1, const void *p2 )
 }
 
 /* get the flags to use for a given channel, possibly setting them too in case of lazy init */
+#undef __wine_dbg_get_channel_flags
 unsigned char __wine_dbg_get_channel_flags( struct __wine_debug_channel *channel )
 {
     if (nb_debug_options == -1) debug_init();
diff --git a/libs/wine/wine.def b/libs/wine/wine.def
index ed315bd08b1..3c88f8a6131 100644
--- a/libs/wine/wine.def
+++ b/libs/wine/wine.def
@@ -1,7 +1,7 @@
 LIBRARY libwine.dll
 
 EXPORTS
-    __wine_dbg_get_channel_flags
+    __wine_dbg_get_channel_flags PRIVATE
     __wine_dbg_set_channel_flags
     __wine_dbg_set_functions
     __wine_dll_register