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authorAlan Stern <stern@rowland.harvard.edu>2006-08-11 16:52:39 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2006-09-27 11:58:54 -0700
commitd5cbad4b8b37acfde3e63d31b92561b87288ad0f (patch)
tree98869f0db85e1f257c5ddd13a2afda934626153a
parent455b25fb209c8241e2163b491228b28667d82c1c (diff)
usbcore: khubd and busy-port handling
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. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--drivers/usb/core/hub.c11
-rw-r--r--drivers/usb/core/hub.h3
2 files changed, 12 insertions, 2 deletions
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 3924dd080be..bdf5be09965 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1658,6 +1658,8 @@ hub_port_resume(struct usb_hub *hub, int port1, struct usb_device *udev)
// 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);
@@ -1707,6 +1709,10 @@ hub_port_resume(struct usb_hub *hub, int port1, struct usb_device *udev)
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;
}
@@ -2690,7 +2696,7 @@ 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:
@@ -2865,6 +2871,9 @@ int usb_reset_device(struct usb_device *udev)
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;
diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h
index 29d5f45a845..0f8e82a4d48 100644
--- a/drivers/usb/core/hub.h
+++ b/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