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Fix a deadlock when trying to power off a USB device. The deadlock

Browse Source 
happens because the code in question is trying to modify the parent
USB port registers outside the USB explore thread.

MFC after:	3 days
This commit is contained in:
hselasky 2013-10-27 10:09:53 +00:00
parent 03a9e9340c
commit 27bcb2607f
4 changed files with 44 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
sys/dev/usb/usb_dev.c
View File

@ -1099,7 +1099,7 @@ usb_ioctl(struct cdev *dev, u_long cmd, caddr_t addr, int fflag, struct thread*
/* Wait for re-enumeration, if any */
while (f->udev->re_enumerate_wait != 0) {
while (f->udev->re_enumerate_wait != USB_RE_ENUM_DONE) {
usb_unref_device(cpd, &refs);

3
sys/dev/usb/usb_device.h
View File

@ -238,6 +238,9 @@ struct usb_device {
uint8_t driver_added_refcount; /* our driver added generation count */
uint8_t power_mode; /* see USB_POWER_XXX */
uint8_t re_enumerate_wait; /* set if re-enum. is in progress */
#define USB_RE_ENUM_DONE 0
#define USB_RE_ENUM_START 1
#define USB_RE_ENUM_PWR_OFF 2
uint8_t ifaces_max; /* number of interfaces present */
uint8_t endpoints_max; /* number of endpoints present */

19
sys/dev/usb/usb_generic.c
View File

@ -1762,16 +1762,11 @@ ugen_set_power_mode(struct usb_fifo *f, int mode)
switch (mode) {
case USB_POWER_MODE_OFF:
/* get the device unconfigured */
err = ugen_set_config(f, USB_UNCONFIG_INDEX);
if (err) {
DPRINTFN(0, "Could not unconfigure "
"device (ignored)\n");
if (udev->flags.usb_mode == USB_MODE_HOST &&
udev->re_enumerate_wait == USB_RE_ENUM_DONE) {
udev->re_enumerate_wait = USB_RE_ENUM_PWR_OFF;
}
/* clear port enable */
err = usbd_req_clear_port_feature(udev->parent_hub,
NULL, udev->port_no, UHF_PORT_ENABLE);
/* set power mode will wake up the explore thread */
break;
case USB_POWER_MODE_ON:
@ -1819,9 +1814,9 @@ ugen_set_power_mode(struct usb_fifo *f, int mode)
/* if we are powered off we need to re-enumerate first */
if (old_mode == USB_POWER_MODE_OFF) {
if (udev->flags.usb_mode == USB_MODE_HOST) {
if (udev->re_enumerate_wait == 0)
udev->re_enumerate_wait = 1;
if (udev->flags.usb_mode == USB_MODE_HOST &&
udev->re_enumerate_wait == USB_RE_ENUM_DONE) {
udev->re_enumerate_wait = USB_RE_ENUM_START;
}
/* set power mode will wake up the explore thread */
}

38
sys/dev/usb/usb_hub.c
View File

@ -248,7 +248,8 @@ uhub_explore_sub(struct uhub_softc *sc, struct usb_port *up)
uint8_t do_unlock;
do_unlock = usbd_enum_lock(child);
if (child->re_enumerate_wait) {
switch (child->re_enumerate_wait) {
case USB_RE_ENUM_START:
err = usbd_set_config_index(child,
USB_UNCONFIG_INDEX);
if (err != 0) {
@ -263,8 +264,33 @@ uhub_explore_sub(struct uhub_softc *sc, struct usb_port *up)
err = usb_probe_and_attach(child,
USB_IFACE_INDEX_ANY);
}
child->re_enumerate_wait = 0;
child->re_enumerate_wait = USB_RE_ENUM_DONE;
err = 0;
break;
case USB_RE_ENUM_PWR_OFF:
/* get the device unconfigured */
err = usbd_set_config_index(child,
USB_UNCONFIG_INDEX);
if (err) {
DPRINTFN(0, "Could not unconfigure "
"device (ignored)\n");
}
/* clear port enable */
err = usbd_req_clear_port_feature(child->parent_hub,
NULL, child->port_no, UHF_PORT_ENABLE);
if (err) {
DPRINTFN(0, "Could not disable port "
"(ignored)\n");
}
child->re_enumerate_wait = USB_RE_ENUM_DONE;
err = 0;
break;
default:
child->re_enumerate_wait = USB_RE_ENUM_DONE;
break;
}
if (do_unlock)
usbd_enum_unlock(child);
@ -2086,7 +2112,7 @@ usb_peer_should_wakeup(struct usb_device *udev)
return (((udev->power_mode == USB_POWER_MODE_ON) &&
(udev->flags.usb_mode == USB_MODE_HOST)) ||
(udev->driver_added_refcount != udev->bus->driver_added_refcount) ||
(udev->re_enumerate_wait != 0) ||
(udev->re_enumerate_wait != USB_RE_ENUM_DONE) ||
(udev->pwr_save.type_refs[UE_ISOCHRONOUS] != 0) ||
(udev->pwr_save.write_refs != 0) ||
((udev->pwr_save.read_refs != 0) &&
@ -2502,6 +2528,8 @@ usbd_set_power_mode(struct usb_device *udev, uint8_t power_mode)
#if USB_HAVE_POWERD
usb_bus_power_update(udev->bus);
#else
usb_needs_explore(udev->bus, 0 /* no probe */ );
#endif
}
@ -2540,8 +2568,8 @@ usbd_filter_power_mode(struct usb_device *udev, uint8_t power_mode)
void
usbd_start_re_enumerate(struct usb_device *udev)
{
if (udev->re_enumerate_wait == 0) {
udev->re_enumerate_wait = 1;
if (udev->re_enumerate_wait == USB_RE_ENUM_DONE) {
udev->re_enumerate_wait = USB_RE_ENUM_START;
usb_needs_explore(udev->bus, 0);
}
}