Document the format of extended capabilities in the '-c' output.

1 files changed, 13 insertions, 1 deletions

diff --git a/usr.sbin/pciconf/pciconf.8 b/usr.sbin/pciconf/pciconf.8
index e1a59fe..72586dd 100644
--- a/usr.sbin/pciconf/pciconf.8
+++ b/usr.sbin/pciconf/pciconf.8
@@ -142,7 +142,7 @@ If the
 option is supplied,
 .Nm
 will list any capabilities supported by each device.
-Each capability will be enumerated via a line in the following format:
+Each capability is enumerated via a line in the following format:
 .Bd -literal
     cap 10[40] = PCI-Express 1 root port
 .Ed
@@ -154,6 +154,18 @@ The second value in the square brackets is the offset of the capability
 in config space in hexadecimal.
 The format of the text after the equals sign is capability-specific.
 .Pp
+Each extended capability is enumerated via a line in a similar format:
+.Bd -literal
+ecap 0002[100] = VC 1 max VC0
+.Ed
+.Pp
+The first value after the
+.Dq Li ecap
+prefix is the extended capability ID in hexadecimal.
+The second value in the square brackets is the offset of the extended
+capability in config space in hexadecimal.
+The format of the text after the equals sign is capability-specific.
+.Pp
 If the
 .Fl v
 option is supplied,