diff options
| author | Alan Stern <stern@rowland.harvard.edu> | 2012-07-11 11:22:26 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-07-16 16:54:25 -0700 |
| commit | df2022553dd8d34d49e16c19d851ea619438f0ef (patch) | |
| tree | 9850c967e0fbee1cb99e900c2e60a0ad50b528da /drivers/usb/host/ehci-hcd.c | |
| parent | 314466101c6ae14f6f5db8a86eda1509ba2c02a8 (diff) | |
USB: EHCI: use hrtimer for interrupt QH unlink
This patch (as1577) adds hrtimer support for unlinking interrupt QHs
in ehci-hcd. The current code relies on a fixed delay of either 2 or
55 us, which is not always adequate and in any case is totally bogus.
Thanks to internal caching, the EHCI hardware may continue to access
an interrupt QH for more than a millisecond after it has been unlinked.
In fact, the EHCI spec doesn't say how long to wait before using an
unlinked interrupt QH. The patch sets the delay to 9 microframes
minimum, which ought to be adequate.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/host/ehci-hcd.c')
| -rw-r--r-- | drivers/usb/host/ehci-hcd.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c index 21d6fbc0a32..edcfd2c4295 100644 --- a/drivers/usb/host/ehci-hcd.c +++ b/drivers/usb/host/ehci-hcd.c @@ -309,6 +309,8 @@ static void ehci_quiesce (struct ehci_hcd *ehci) static void end_unlink_async(struct ehci_hcd *ehci); static void ehci_work(struct ehci_hcd *ehci); +static void start_unlink_intr(struct ehci_hcd *ehci, struct ehci_qh *qh); +static void end_unlink_intr(struct ehci_hcd *ehci, struct ehci_qh *qh); #include "ehci-timer.c" #include "ehci-hub.c" @@ -1034,7 +1036,7 @@ static int ehci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status) switch (qh->qh_state) { case QH_STATE_LINKED: case QH_STATE_COMPLETING: - intr_deschedule (ehci, qh); + start_unlink_intr(ehci, qh); break; case QH_STATE_IDLE: qh_completions (ehci, qh); @@ -1164,7 +1166,7 @@ ehci_endpoint_reset(struct usb_hcd *hcd, struct usb_host_endpoint *ep) if (eptype == USB_ENDPOINT_XFER_BULK) unlink_async(ehci, qh); else - intr_deschedule(ehci, qh); + start_unlink_intr(ehci, qh); } } spin_unlock_irqrestore(&ehci->lock, flags); |