diff -c -r old/docs/man/man1/showkey.1 kbd-2.4.0/docs/man/man1/showkey.1
*** old/docs/man/man1/showkey.1 2020-12-15 22:32:21.000000000 +0800
--- kbd-2.4.0/docs/man/man1/showkey.1   2021-12-03 22:01:27.702550615 +0800
***************
*** 84,89 ****
--- 84,102 ----
  to know the scan codes sent by various keys it is better to boot a
  2.4 kernel. Since 2.6.9 there also is the boot option atkbd.softraw=0
  that tells the 2.6 kernel to return the actual scan codes.
+
+ .SH NOTES
+ The raw scan codes are available only on AT and PS/2 keyboards,
+ and even then they are disabled unless the
+ .B atkbd.softraw=0
+ kernel parameter is used.
+ When the raw scan codes are not available, the kernel uses a fixed built-in
+ table to produce scan codes from keycodes.  Thus,
+ .BR setkeycodes (8)
+ can affect the output of
+ .B showkey
+ in scan code dump mode.
+
  .SH "SEE ALSO"
  .BR loadkeys (1),
  .BR dumpkeys (1),
diff -c -r old/docs/man/man8/setkeycodes.8 kbd-2.4.0/docs/man/man8/setkeycodes.8
*** old/docs/man/man8/setkeycodes.8     2020-12-15 22:32:21.000000000 +0800
--- kbd-2.4.0/docs/man/man8/setkeycodes.8       2021-12-03 22:02:45.193516342 +0800
***************
*** 42,47 ****
--- 42,51 ----
  will assign the keycode 112 to it, and then
  .BR loadkeys (1)
  can be used to define the function of this key.
+
+ USB keyboards have standardized keycodes and
+ .B setkeycodes
+ doesn't affect them at all.
  .LP
  Some older kernels might hardwire a low scancode range to the
  equivalent keycodes; setkeycodes will fail when you try to remap
***************
*** 60,65 ****
--- 64,77 ----
  .SH BUGS
  The keycodes of X have nothing to do with those of Linux.
  Unusual keys can be made visible under Linux, but not under X.
+
+ .B setkeycodes
+ affects only the "first" input device
+ that has modifiable scancode-to-keycode mapping.
+ If there is more than one such device,
+ .B setkeycodes
+ cannot change the mapping of other devices than the "first" one.
+
  .SH "SEE ALSO"
  .BR dumpkeys (1),
  .BR loadkeys (1),
~