Allow regular off-the-shelf keyboards to be overclocked like so-called

"Gamers Keyboards" by adding a tunable, "hw.usb.ukbd.pollrate", which
can fix the polling rate of the attached USB keyboards in the range
1..1000Hz. A similar feature already exists in the USB mouse
driver. Use with care! Might leave you without keyboard input. This
feature is only available when the USB_DEBUG option is set in the
kernel configuration file.

Correct "unit" type to "int" while at it.

1 files changed, 22 insertions, 3 deletions

diff --git a/sys/dev/usb/input/ukbd.c b/sys/dev/usb/input/ukbd.c
index 0c56ce0..770c8fc 100644
--- a/sys/dev/usb/input/ukbd.c
+++ b/sys/dev/usb/input/ukbd.c
@@ -92,14 +92,18 @@ __FBSDID("$FreeBSD$");
 #ifdef USB_DEBUG
 static int ukbd_debug = 0;
 static int ukbd_no_leds = 0;
+static int ukbd_pollrate = 0;
 
-static SYSCTL_NODE(_hw_usb, OID_AUTO, ukbd, CTLFLAG_RW, 0, "USB ukbd");
+static SYSCTL_NODE(_hw_usb, OID_AUTO, ukbd, CTLFLAG_RW, 0, "USB keyboard");
 SYSCTL_INT(_hw_usb_ukbd, OID_AUTO, debug, CTLFLAG_RW | CTLFLAG_TUN,
     &ukbd_debug, 0, "Debug level");
 TUNABLE_INT("hw.usb.ukbd.debug", &ukbd_debug);
 SYSCTL_INT(_hw_usb_ukbd, OID_AUTO, no_leds, CTLFLAG_RW | CTLFLAG_TUN,
     &ukbd_no_leds, 0, "Disables setting of keyboard leds");
 TUNABLE_INT("hw.usb.ukbd.no_leds", &ukbd_no_leds);
+SYSCTL_INT(_hw_usb_ukbd, OID_AUTO, pollrate, CTLFLAG_RW | CTLFLAG_TUN,
+    &ukbd_pollrate, 0, "Force this polling rate, 1-1000Hz");
+TUNABLE_INT("hw.usb.ukbd.pollrate", &ukbd_pollrate);
 #endif
 
 #define	UKBD_EMULATE_ATSCANCODE	       1
@@ -1165,13 +1169,15 @@ ukbd_attach(device_t dev)
 {
 	struct ukbd_softc *sc = device_get_softc(dev);
 	struct usb_attach_arg *uaa = device_get_ivars(dev);
-	int32_t unit = device_get_unit(dev);
+	int unit = device_get_unit(dev);
 	keyboard_t *kbd = &sc->sc_kbd;
 	void *hid_ptr = NULL;
 	usb_error_t err;
 	uint16_t n;
 	uint16_t hid_len;
-
+#ifdef USB_DEBUG
+	int rate;
+#endif
 	UKBD_LOCK_ASSERT();
 
 	kbd_init_struct(kbd, UKBD_DRIVER_NAME, KB_OTHER, unit, 0, 0, 0);
@@ -1272,6 +1278,19 @@ ukbd_attach(device_t dev)
 		genkbd_diag(kbd, bootverbose);
 	}
 
+#ifdef USB_DEBUG
+	/* check for polling rate override */
+	rate = ukbd_pollrate;
+	if (rate > 0) {
+		if (rate > 1000)
+			rate = 1;
+		else
+			rate = 1000 / rate;
+
+		/* set new polling interval in ms */
+		usbd_xfer_set_interval(sc->sc_xfer[UKBD_INTR_DT], rate);
+	}
+#endif
 	/* start the keyboard */
 	usbd_transfer_start(sc->sc_xfer[UKBD_INTR_DT]);