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USB: automatically enable RHSC interrupts

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This patch (as1069c) changes the way OHCI root-hub status-change
interrupts are enabled.  Currently a special HCD method,
hub_irq_enable(), is called when the hub driver is finished using a
root hub.  This approach turns out to be subject to races, resulting
in unnecessary polling.

The patch does away with the method entirely.  Instead, the driver
automatically enables the RHSC interrupt when no more status changes
are present.  This scheme is safe with controllers using
level-triggered semantics for their interrupt flags.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Alan Stern
2008-08-20 17:22:05 -04:00
committed by Greg Kroah-Hartman
parent 5096aedcd2
commit b5fb454f69
22 changed files with 31 additions and 72 deletions
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9
drivers/usb/core/hub.c
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@@ -2102,8 +2102,6 @@ int usb_port_resume(struct usb_device *udev)
}
clear_bit(port1, hub->busy_bits);
if (!hub->hdev->parent && !hub->busy_bits[0])
usb_enable_root_hub_irq(hub->hdev->bus);
status = check_port_resume_type(udev,
hub, port1, status, portchange, portstatus);
@@ -3081,11 +3079,6 @@ 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 && !hub->busy_bits[0])
usb_enable_root_hub_irq(hdev->bus);
loop_autopm:
/* Allow autosuspend if we're not going to run again */
if (list_empty(&hub->event_list))
@@ -3311,8 +3304,6 @@ static int usb_reset_and_verify_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;