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USB: EHCI: EHCI 1.1 addendum: Enable Per-port change detect bits

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This patch will enable Per-port event feature defined in EHCI 1.1
addendum. This feature addresses an issue where HCD is currently
required to read and parse PORTSC for all enabled root hub ports. With
this patch, the overhead will be reduced.

Signed-off-by: Alek Du <alek.du@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Alek Du
2010-06-04 15:47:56 +08:00
committed by Greg Kroah-Hartman
parent 48f2497014
commit 5a9cdf332e
3 changed files with 27 additions and 2 deletions
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9
drivers/usb/host/ehci-hub.c
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@@ -603,6 +603,7 @@ ehci_hub_status_data (struct usb_hcd *hcd, char *buf)
u32 mask;
int ports, i, retval = 1;
unsigned long flags;
u32 ppcd = 0;
/* if !USB_SUSPEND, root hub timers won't get shut down ... */
if (!HC_IS_RUNNING(hcd->state))
@@ -632,7 +633,15 @@ ehci_hub_status_data (struct usb_hcd *hcd, char *buf)
/* port N changes (bit N)? */
spin_lock_irqsave (&ehci->lock, flags);
/* get per-port change detect bits */
if (ehci->has_ppcd)
ppcd = ehci_readl(ehci, &ehci->regs->status) >> 16;
for (i = 0; i < ports; i++) {
/* leverage per-port change bits feature */
if (ehci->has_ppcd && !(ppcd & (1 << i)))
continue;
temp = ehci_readl(ehci, &ehci->regs->port_status [i]);
/*