added documentation of hacks

diff --git a/Documentation/comedi/hacks b/Documentation/comedi/hacks
new file mode 100644 (file)
index 0000000..981c33f
--- /dev/null
+++ b/Documentation/comedi/hacks
@@ -0,0 +1,20 @@
+
+A list of some of the hacks in the low-level drivers.  If
+you want to use a hack in a different driver, please fix the
+hack instead of duplicating it.
+
+
+- Extended configuration:  the daqboard2000 driver loads about
+  40 kB of FPGA programming information at device configuration.
+  It does this by overloading option[0] and option[1] with the
+  address and length of the programming data.  A corresponding
+  hack in comedi_config allows one to specify a file to be loaded
+  as the FPGA data.  Fix:  change the devconfig interface to
+  make this standard.
+
+- Autocalibration input:  the ni_mio_common driver uses AREF_OTHER
+  to access stable voltage references on the board.  It's not the
+  best method, but it is only supposed to be accessed by
+  comedi_calibrate.
+
+