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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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4
drivers/usb/core/hcd.h
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@@ -212,8 +212,6 @@ struct hc_driver {
int (*bus_suspend)(struct usb_hcd *);
int (*bus_resume)(struct usb_hcd *);
int (*start_port_reset)(struct usb_hcd *, unsigned port_num);
void (*hub_irq_enable)(struct usb_hcd *);
/* Needed only if port-change IRQs are level-triggered */
/* force handover of high-speed port to full-speed companion */
void (*relinquish_port)(struct usb_hcd *, int);
@@ -379,8 +377,6 @@ extern struct list_head usb_bus_list;
extern struct mutex usb_bus_list_lock;
extern wait_queue_head_t usb_kill_urb_queue;
extern void usb_enable_root_hub_irq(struct usb_bus *bus);
extern int usb_find_interface_driver(struct usb_device *dev,
struct usb_interface *interface);