diff --git a/prog/detect/i2cdetect.c b/prog/detect/i2cdetect.c
index b5b8c974..a612d6ef 100644
--- a/prog/detect/i2cdetect.c
+++ b/prog/detect/i2cdetect.c
@@ -36,6 +36,7 @@ int main(int argc, char *argv[])
   char *end;
   int i,j,res,i2cbus,file;
   char filename[20];
+  long funcs;
   
 
   if (argc < 2) {
@@ -61,6 +62,19 @@ int main(int argc, char *argv[])
             strerror(errno));
     exit(1);
   }
+
+  if (ioctl(file,I2C_FUNCS,&funcs) < 0) {
+    fprintf(stderr,
+            "Error: Could not get the adapter functionality maxtrix: %s\n",
+            strerror(errno));
+    exit(1);
+  }
+  if (! (funcs & I2C_FUNC_SMBUS_QUICK)) {
+    fprintf(stderr,
+            "Error: Can't use SMBus Quick Write command "
+            "on this bus (ISA bus?)\n");
+    exit(1);
+  }
   
   fprintf(stderr,"  WARNING! This program can confuse your I2C bus, "
           "cause data loss and worse!\n");