Author: thompsa
Date: Fri Mar 6 17:13:12 2009
New Revision: 189453
URL: http://svn.freebsd.org/changeset/base/189453
Log:
MFp4 //depot/projects/u...@158692
Workaround a EHCI performance problem by issuing a doorbell after queueing a
bulk xfer.
Submitted by: Hans Petter Selasky
Modified:
head/sys/dev/usb/controller/ehci.c
Modified: head/sys/dev/usb/controller/ehci.c
==============================================================================
--- head/sys/dev/usb/controller/ehci.c Fri Mar 6 17:04:47 2009
(r189452)
+++ head/sys/dev/usb/controller/ehci.c Fri Mar 6 17:13:12 2009
(r189453)
@@ -2189,12 +2189,21 @@ static void
ehci_device_bulk_start(struct usb2_xfer *xfer)
{
ehci_softc_t *sc = EHCI_BUS2SC(xfer->xroot->bus);
+ uint32_t temp;
/* setup TD's and QH */
ehci_setup_standard_chain(xfer, &sc->sc_async_p_last);
/* put transfer on interrupt queue */
ehci_transfer_intr_enqueue(xfer);
+
+ /* XXX Performance quirk: Some Host Controllers have a too low
+ * interrupt rate. Issue an IAAD to stimulate the Host
+ * Controller after queueing the BULK transfer.
+ */
+ temp = EOREAD4(sc, EHCI_USBCMD);
+ if (!(temp & EHCI_CMD_IAAD))
+ EOWRITE4(sc, EHCI_USBCMD, temp | EHCI_CMD_IAAD);
}
struct usb2_pipe_methods ehci_device_bulk_methods =
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