[.joined/src/trunk]: .joined/src/sys/dev/usb ukbd(4): Avoid races in LED sett...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/.joined/src/rev/06b9bbf7ea99
branches:  trunk
changeset: 359338:06b9bbf7ea99
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Fri Dec 31 14:24:06 2021 +0000

description:
ukbd(4): Avoid races in LED setting on attach.

- Don't reuse sc_delay for LED task -- a keyboard interrupt shortly
  after attach might reset sc_delay so that the LEDs never get turned
  back off.

- Don't turn the LEDs back off after attach if something else has
  already changed them by the time the callout fires.

(And make sure to callout_halt before done this time!)

diffstat:

 sys/dev/usb/ukbd.c |  20 +++++++++++++++++---
 1 files changed, 17 insertions(+), 3 deletions(-)

diffs (73 lines):

diff -r 07ec21e944c3 -r 06b9bbf7ea99 sys/dev/usb/ukbd.c
--- a/sys/dev/usb/ukbd.c        Fri Dec 31 14:22:42 2021 +0000
+++ b/sys/dev/usb/ukbd.c        Fri Dec 31 14:24:06 2021 +0000
@@ -1,4 +1,4 @@
-/*      $NetBSD: ukbd.c,v 1.155 2021/12/26 16:08:21 andvar Exp $        */
+/*      $NetBSD: ukbd.c,v 1.156 2021/12/31 14:24:06 riastradh Exp $        */
 
 /*
  * Copyright (c) 1998 The NetBSD Foundation, Inc.
@@ -35,7 +35,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ukbd.c,v 1.155 2021/12/26 16:08:21 andvar Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ukbd.c,v 1.156 2021/12/31 14:24:06 riastradh Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_ddb.h"
@@ -270,6 +270,8 @@
        struct hid_location sc_compose;
        int sc_leds;
        struct usb_task sc_ledtask;
+       struct callout sc_ledreset;
+       int sc_leds_set;
        device_t sc_wskbddev;
 
 #if defined(WSDISPLAY_COMPAT_RAWKBD)
@@ -483,11 +485,13 @@
        sc->sc_data_r = 0;
 
        usb_init_task(&sc->sc_ledtask, ukbd_set_leds_task, sc, 0);
+       callout_init(&sc->sc_ledreset, 0);
 
        /* Flash the leds; no real purpose, just shows we're alive. */
        ukbd_set_leds(sc, WSKBD_LED_SCROLL | WSKBD_LED_NUM | WSKBD_LED_CAPS
                        | WSKBD_LED_COMPOSE);
-       callout_reset(&sc->sc_delay, mstohz(400), ukbd_delayed_leds_off, sc);
+       callout_reset(&sc->sc_ledreset, mstohz(400), ukbd_delayed_leds_off,
+           sc);
 
        sc->sc_wskbddev = config_found(self, &a, wskbddevprint, CFARGS_NONE);
 
@@ -573,6 +577,7 @@
                rv = config_detach(sc->sc_wskbddev, flags);
 
        callout_halt(&sc->sc_delay, NULL);
+       callout_halt(&sc->sc_ledreset, NULL);
        usb_rem_task_wait(sc->sc_hdev.sc_parent->sc_udev, &sc->sc_ledtask,
            USB_TASKQ_DRIVER, NULL);
 
@@ -715,6 +720,13 @@
 {
        struct ukbd_softc *sc = addr;
 
+       /*
+        * If the LEDs have already been set after attach, other than
+        * by our initial flashing of them, leave them be.
+        */
+       if (sc->sc_leds_set)
+               return;
+
        ukbd_set_leds(sc, 0);
 }
 
@@ -880,6 +892,8 @@
        if (sc->sc_dying)
                return;
 
+       sc->sc_leds_set = 1;
+
        if (sc->sc_leds == leds)
                return;