diff -up kbd-2.3.0/docs/man/man1/showkey.1.orig kbd-2.3.0/docs/man/man1/showkey.1
--- kbd-2.3.0/docs/man/man1/showkey.1.orig	2020-07-08 19:25:47.000000000 +0200
+++ kbd-2.3.0/docs/man/man1/showkey.1	2020-07-16 08:56:15.970254183 +0200
@@ -84,6 +84,19 @@ corresponds to what the keyboard hardwar
 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 -up kbd-2.3.0/docs/man/man8/setkeycodes.8.orig kbd-2.3.0/docs/man/man8/setkeycodes.8
--- kbd-2.3.0/docs/man/man8/setkeycodes.8.orig	2020-07-08 19:35:35.000000000 +0200
+++ kbd-2.3.0/docs/man/man8/setkeycodes.8	2020-07-16 08:57:52.293900997 +0200
@@ -42,6 +42,10 @@ the command
 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
@@ -60,6 +64,14 @@ None.
 .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),