Author: hselasky
Date: Wed Jul 13 21:07:50 2011
New Revision: 223989
URL: http://svn.freebsd.org/changeset/base/223989
Log:
Fix for dump after shutdown with USB keyboard plugged in. It appears that the
system timer is stopped during shutdown and that the pause() statement in ukbd
causes infinite hang in this regard. The fix is to use mi_switch() instead of
pause() to do the required task switch to ensure that the required USB
processes
get executed.
Reported by: mike_kar...@mcafee.com
MFC after: 1 week
Modified:
head/sys/dev/usb/input/ukbd.c
Modified: head/sys/dev/usb/input/ukbd.c
==============================================================================
--- head/sys/dev/usb/input/ukbd.c Wed Jul 13 21:07:41 2011
(r223988)
+++ head/sys/dev/usb/input/ukbd.c Wed Jul 13 21:07:50 2011
(r223989)
@@ -59,6 +59,8 @@ __FBSDID("$FreeBSD$");
#include <sys/callout.h>
#include <sys/malloc.h>
#include <sys/priv.h>
+#include <sys/proc.h>
+#include <sys/sched.h>
#include <sys/kdb.h>
#include <dev/usb/usb.h>
@@ -386,6 +388,33 @@ ukbd_put_key(struct ukbd_softc *sc, uint
}
static void
+ukbd_yield(void)
+{
+ struct thread *td = curthread;
+ uint32_t old_prio;
+
+ DROP_GIANT();
+
+ thread_lock(td);
+
+ /* get current priority */
+ old_prio = td->td_base_pri;
+
+ /* set new priority */
+ sched_prio(td, td->td_user_pri);
+
+ /* cause a task switch */
+ mi_switch(SW_INVOL | SWT_RELINQUISH, NULL);
+
+ /* restore priority */
+ sched_prio(td, old_prio);
+
+ thread_unlock(td);
+
+ PICKUP_GIANT();
+}
+
+static void
ukbd_do_poll(struct ukbd_softc *sc, uint8_t wait)
{
DPRINTFN(2, "polling\n");
@@ -396,8 +425,9 @@ ukbd_do_poll(struct ukbd_softc *sc, uint
if (kdb_active == 0) {
while (sc->sc_inputs == 0) {
- /* make sure the USB code gets a chance to run */
- pause("UKBD", 1);
+
+ /* give USB threads a chance to run */
+ ukbd_yield();
/* check if we should wait */
if (!wait)
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