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usb: PS3 EHCI QH read work-around 

PS3 EHCI HC errata fix 244.  The SCC EHCI HC will not correctly perform QH
reads that occur near or span a micro-frame boundry.  This is due to a problem
in the Nak Count Reload Control logic (EHCI Specification 1.0 Section 4.9.1).

The work-around for this problem is for the HC driver to set I=1 (inactive) for
QHs with H=1 (list head).

Signed-off-by: Geoff Levand <geoff@infradead.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
hifive-unleashed-5.1
Geoff Levand 2011-11-08 16:01:18 -08:00
parent df7c1ca229
commit aaa0ef289a
1 changed files with 1 additions and 0 deletions
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drivers/usb/host/ehci-hcd.c
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@ -670,6 +670,7 @@ static int ehci_init(struct usb_hcd *hcd)
hw = ehci->async->hw;
hw->hw_next = QH_NEXT(ehci, ehci->async->qh_dma);
hw->hw_info1 = cpu_to_hc32(ehci, QH_HEAD);
hw->hw_info1 |= cpu_to_hc32(ehci, (1 << 7)); /* I = 1 */
hw->hw_token = cpu_to_hc32(ehci, QTD_STS_HALT);
hw->hw_qtd_next = EHCI_LIST_END(ehci);
ehci->async->qh_state = QH_STATE_LINKED;