Greg:
We don't want khubd to start interfering in the device-resume process
merely because the PORT_STATUS_C_SUSPEND feature happens to be set.
Ports need to be marked as busy while a resume is taking place.
In addition, so long as ports are marked as busy, khubd won't be able
to clear their various status-change features. On an interrupt-driven
root hub this could lead to an interrupt storm. Root hub IRQs should
not be re-enabled until the busy_bits value is equal to 0.
This patch (as765) fixes these two potential problems.
Alan Stern
Signed-off-by: Alan Stern <[EMAIL PROTECTED]>
---
Index: usb-2.6/drivers/usb/core/hub.c
===================================================================
--- usb-2.6.orig/drivers/usb/core/hub.c
+++ usb-2.6/drivers/usb/core/hub.c
@@ -1668,6 +1668,8 @@ hub_port_resume(struct usb_hub *hub, int
// dev_dbg(hub->intfdev, "resume port %d\n", port1);
+ set_bit(port1, hub->busy_bits);
+
/* see 7.1.7.7; affects power usage, but not budgeting */
status = clear_port_feature(hub->hdev,
port1, USB_PORT_FEAT_SUSPEND);
@@ -1717,6 +1719,10 @@ hub_port_resume(struct usb_hub *hub, int
if (status < 0)
hub_port_logical_disconnect(hub, port1);
+ clear_bit(port1, hub->busy_bits);
+ if (!hub->hdev->parent && !hub->busy_bits[0])
+ usb_enable_root_hub_irq(hub->hdev->bus);
+
return status;
}
@@ -2700,7 +2706,7 @@ static void hub_events(void)
/* If this is a root hub, tell the HCD it's okay to
* re-enable port-change interrupts now. */
- if (!hdev->parent)
+ if (!hdev->parent && !hub->busy_bits[0])
usb_enable_root_hub_irq(hdev->bus);
loop:
@@ -2875,6 +2881,9 @@ int usb_reset_device(struct usb_device *
break;
}
clear_bit(port1, parent_hub->busy_bits);
+ if (!parent_hdev->parent && !parent_hub->busy_bits[0])
+ usb_enable_root_hub_irq(parent_hdev->bus);
+
if (ret < 0)
goto re_enumerate;
Index: usb-2.6/drivers/usb/core/hub.h
===================================================================
--- usb-2.6.orig/drivers/usb/core/hub.h
+++ usb-2.6/drivers/usb/core/hub.h
@@ -212,7 +212,8 @@ struct usb_hub {
unsigned long event_bits[1]; /* status change bitmask */
unsigned long change_bits[1]; /* ports with logical connect
status change */
- unsigned long busy_bits[1]; /* ports being reset */
+ unsigned long busy_bits[1]; /* ports being reset or
+ resumed */
#if USB_MAXCHILDREN > 31 /* 8*sizeof(unsigned long) - 1 */
#error event_bits[] is too short!
#endif
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