On Tue, 2011-11-15 at 11:57 -0500, Alan Stern wrote: > On Tue, 15 Nov 2011, Geoff Levand wrote: > > > 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). > > > > diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c > > index e43cb5a..4ff0b7e 100644 > > --- a/drivers/usb/host/ehci-hcd.c > > +++ b/drivers/usb/host/ehci-hcd.c > > @@ -621,6 +621,7 @@ static int ehci_init(struct usb_hcd *hcd) > > 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, (2 << 28)); /* RL = 2 */ > > + 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; > > This should be okay, although the RL stuff isn't needed. Have you > tested it on desktop PCs? No, I will try it and report. Just as a side note, I would certainly appreciate if you could request any future desktop PC related changes be tested on a PS3... -Geoff -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
