diff --git a/sbin/atacontrol/atacontrol.8 b/sbin/atacontrol/atacontrol.8
index 3899e9b4009c..003a4bf14d26 100644
--- a/sbin/atacontrol/atacontrol.8
+++ b/sbin/atacontrol/atacontrol.8
@@ -172,6 +172,20 @@ If one of the devices mode should not be changed, use a nonexisting mode
 as argument (i.e.\&
 .Dq Li XXX ) ,
 and the mode will remain unchanged.
+.Pp
+Currently supported modes are :
+.Dq Li BIOSDMA ,
+.Dq Li PIO0 (alias BIOSPIO) ,
+.Dq Li PIO1 ,
+.Dq Li PIO2 ,
+.Dq Li PIO3 ,
+.Dq Li PIO4 ,
+.Dq Li WDMA2 ,
+.Dq Li UDMA2 (alias UDMA33) ,
+.Dq Li UDMA4 (alias UDMA66) ,
+.Dq Li UDMA5 (alias UDMA100)
+and
+.Dq Li UDMA6 (alias UDMA133) .
 .It Ic info
 Show info about the attached devices on the
 .Ar channel .
@@ -188,6 +202,26 @@ Fan RPM speed, enclosure temperature, 5V and 12V levels are shown.
 .It Ic list
 Show info about all attached devices on all active controllers.
 .El
+.Sh EXAMPLES
+To see the devices' current access modes, use the command line:
+.Pp
+.Dl atacontrol mode 0
+.Pp
+which results in the modes of the devices being displayed as a string
+like this:
+.Pp
+.Dl Master = WDMA2
+.Dl Slave  = PIO4
+.Pp
+This means that ata0-master is in DMA mode,
+ata0-slave is in PIO mode,
+and so forth.
+You can set the mode with atacontrol and a string like the above,
+for example:
+.Pp
+.Dl atacontrol mode 0 PIO4 PIO4
+.Pp
+The new modes are set as soon as the atacontrol command returns.
 .Sh SEE ALSO
 .Xr ata 4
 .Sh HISTORY