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USB: simplify hub_restart() logic
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This patch (as1081) straightens out the logic of the hub_restart()
routine.  Each port of the hub is scanned and the driver makes sure
that ports which are supposed to be disabled really _are_ disabled.
Any ports with a significant change in status are flagged in
hub->change_bits, so that khubd can focus on them without the need to
scan all the ports a second time -- which means the hub->activating
flag is no longer needed.

Also, it is now recognized explicitly that the only reason for
resuming a port which was not suspended is to carry out a reset-resume
operation, which happens only in a non-CONFIG_USB_SUSPEND setting.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Alan Stern authored and Greg Kroah-Hartman committed Jul 21, 2008
1 parent 9e5eace commit 6ee0b27
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Showing 2 changed files with 54 additions and 67 deletions.
7 changes: 1 addition & 6 deletions drivers/usb/core/driver.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -805,8 +805,6 @@ static int usb_resume_device(struct usb_device *udev)

if (udev->state == USB_STATE_NOTATTACHED)
goto done;
if (udev->state != USB_STATE_SUSPENDED && !udev->reset_resume)
goto done;

/* Can't resume it if it doesn't have a driver. */
if (udev->dev.driver == NULL) {
Expand Down Expand Up @@ -1173,11 +1171,8 @@ static int usb_resume_both(struct usb_device *udev)
* then we're stuck. */
status = usb_resume_device(udev);
}
} else {

/* Needed for reset-resume */
} else if (udev->reset_resume)
status = usb_resume_device(udev);
}

if (status == 0 && udev->actconfig) {
for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
Expand Down
114 changes: 53 additions & 61 deletions drivers/usb/core/hub.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -72,7 +72,6 @@ struct usb_hub {

unsigned limited_power:1;
unsigned quiescing:1;
unsigned activating:1;
unsigned disconnected:1;

unsigned has_indicators:1;
Expand Down Expand Up @@ -539,7 +538,6 @@ static void hub_quiesce(struct usb_hub *hub)
{
/* (nonblocking) khubd and related activity won't re-trigger */
hub->quiescing = 1;
hub->activating = 0;

/* (blocking) stop khubd and related activity */
usb_kill_urb(hub->urb);
Expand All @@ -554,7 +552,6 @@ static void hub_activate(struct usb_hub *hub)
int status;

hub->quiescing = 0;
hub->activating = 1;

status = usb_submit_urb(hub->urb, GFP_NOIO);
if (status < 0)
Expand Down Expand Up @@ -638,81 +635,83 @@ static void hub_stop(struct usb_hub *hub)
hub_quiesce(hub);
}

#define HUB_RESET 1
#define HUB_RESUME 2
#define HUB_RESET_RESUME 3

#ifdef CONFIG_PM
enum hub_activation_type {
HUB_INIT, HUB_POST_RESET, HUB_RESUME, HUB_RESET_RESUME
};

static void hub_restart(struct usb_hub *hub, int type)
static void hub_restart(struct usb_hub *hub, enum hub_activation_type type)
{
struct usb_device *hdev = hub->hdev;
int port1;

/* Check each of the children to see if they require
* USB-PERSIST handling or disconnection. Also check
* each unoccupied port to make sure it is still disabled.
/* Check each port and set hub->change_bits to let khubd know
* which ports need attention.
*/
for (port1 = 1; port1 <= hdev->maxchild; ++port1) {
struct usb_device *udev = hdev->children[port1-1];
int status = 0;
int status;
u16 portstatus, portchange;

if (!udev || udev->state == USB_STATE_NOTATTACHED) {
if (type != HUB_RESET) {
status = hub_port_status(hub, port1,
&portstatus, &portchange);
if (status == 0 && (portstatus &
USB_PORT_STAT_ENABLE))
clear_port_feature(hdev, port1,
USB_PORT_FEAT_ENABLE);
}
continue;
portstatus = portchange = 0;
status = hub_port_status(hub, port1, &portstatus, &portchange);
if (udev || (portstatus & USB_PORT_STAT_CONNECTION))
dev_dbg(hub->intfdev,
"port %d: status %04x change %04x\n",
port1, portstatus, portchange);

/* After anything other than HUB_RESUME (i.e., initialization
* or any sort of reset), every port should be disabled.
* Unconnected ports should likewise be disabled (paranoia),
* and so should ports for which we have no usb_device.
*/
if ((portstatus & USB_PORT_STAT_ENABLE) && (
type != HUB_RESUME ||
!(portstatus & USB_PORT_STAT_CONNECTION) ||
!udev ||
udev->state == USB_STATE_NOTATTACHED)) {
clear_port_feature(hdev, port1, USB_PORT_FEAT_ENABLE);
portstatus &= ~USB_PORT_STAT_ENABLE;
}

/* Was the power session lost while we were suspended? */
switch (type) {
case HUB_RESET_RESUME:
portstatus = 0;
portchange = USB_PORT_STAT_C_CONNECTION;
break;

case HUB_RESET:
case HUB_RESUME:
status = hub_port_status(hub, port1,
&portstatus, &portchange);
break;
}
if (!udev || udev->state == USB_STATE_NOTATTACHED) {
/* Tell khubd to disconnect the device or
* check for a new connection
*/
if (udev || (portstatus & USB_PORT_STAT_CONNECTION))
set_bit(port1, hub->change_bits);

} else if (portstatus & USB_PORT_STAT_ENABLE) {
/* The power session apparently survived the resume.
* If there was an overcurrent or suspend change
* (i.e., remote wakeup request), have khubd
* take care of it.
*/
if (portchange)
set_bit(port1, hub->change_bits);

/* For "USB_PERSIST"-enabled children we must
* mark the child device for reset-resume and
* turn off the various status changes to prevent
* khubd from disconnecting it later.
*/
if (udev->persist_enabled && status == 0 &&
!(portstatus & USB_PORT_STAT_ENABLE)) {
} else if (udev->persist_enabled) {
/* Turn off the status changes to prevent khubd
* from disconnecting the device.
*/
if (portchange & USB_PORT_STAT_C_ENABLE)
clear_port_feature(hub->hdev, port1,
USB_PORT_FEAT_C_ENABLE);
if (portchange & USB_PORT_STAT_C_CONNECTION)
clear_port_feature(hub->hdev, port1,
USB_PORT_FEAT_C_CONNECTION);
#ifdef CONFIG_PM
udev->reset_resume = 1;
#endif
} else {
/* The power session is gone; tell khubd */
usb_set_device_state(udev, USB_STATE_NOTATTACHED);
set_bit(port1, hub->change_bits);
}

/* Otherwise for a reset_resume we must disconnect the child,
* but as we may not lock the child device here
* we have to do a "logical" disconnect.
*/
else if (type == HUB_RESET_RESUME)
hub_port_logical_disconnect(hub, port1);
}

hub_activate(hub);
}

#endif /* CONFIG_PM */

/* caller has locked the hub device */
static int hub_pre_reset(struct usb_interface *intf)
{
Expand All @@ -728,7 +727,7 @@ static int hub_post_reset(struct usb_interface *intf)
struct usb_hub *hub = usb_get_intfdata(intf);

hub_power_on(hub);
hub_activate(hub);
hub_restart(hub, HUB_POST_RESET);
return 0;
}

Expand Down Expand Up @@ -2903,19 +2902,14 @@ static void hub_events(void)
continue;
connect_change = test_bit(i, hub->change_bits);
if (!test_and_clear_bit(i, hub->event_bits) &&
!connect_change && !hub->activating)
!connect_change)
continue;

ret = hub_port_status(hub, i,
&portstatus, &portchange);
if (ret < 0)
continue;

if (hub->activating && !hdev->children[i-1] &&
(portstatus &
USB_PORT_STAT_CONNECTION))
connect_change = 1;

if (portchange & USB_PORT_STAT_C_CONNECTION) {
clear_port_feature(hdev, i,
USB_PORT_FEAT_C_CONNECTION);
Expand Down Expand Up @@ -3011,8 +3005,6 @@ static void hub_events(void)
}
}

hub->activating = 0;

/* If this is a root hub, tell the HCD it's okay to
* re-enable port-change interrupts now. */
if (!hdev->parent && !hub->busy_bits[0])
Expand Down

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