From af3a23ef4e5fbaf33f0afdda7d26442f036ba795 Mon Sep 17 00:00:00 2001 From: Sarah Sharp Date: Mon, 25 Jun 2012 08:24:30 -0700 Subject: xhci: Export Latency Tolerance Messaging capabilities. Some xHCI host controllers may have optional support for Latency Tolerance Messaging (LTM). This allows USB 3.0 devices that support LTM to pass information about how much latency they can tolerate to the xHC. A PCI xHCI host will use this information to update the PCI Latency Tolerance Request (LTR) info. The goal of this is to gather latency information for the system, to enable hardware-driven C states, and the shutting down of PLLs. Signed-off-by: Sarah Sharp --- drivers/usb/host/xhci-hub.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c index 2732ef660c5c..6d21030e2b7b 100644 --- a/drivers/usb/host/xhci-hub.c +++ b/drivers/usb/host/xhci-hub.c @@ -508,12 +508,18 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue, if (hcd->speed != HCD_USB3) goto error; + /* Set the U1 and U2 exit latencies. */ memcpy(buf, &usb_bos_descriptor, USB_DT_BOS_SIZE + USB_DT_USB_SS_CAP_SIZE); temp = xhci_readl(xhci, &xhci->cap_regs->hcs_params3); buf[12] = HCS_U1_LATENCY(temp); put_unaligned_le16(HCS_U2_LATENCY(temp), &buf[13]); + /* Indicate whether the host has LTM support. */ + temp = xhci_readl(xhci, &xhci->cap_regs->hcc_params); + if (HCC_LTC(temp)) + buf[8] |= USB_LTM_SUPPORT; + spin_unlock_irqrestore(&xhci->lock, flags); return USB_DT_BOS_SIZE + USB_DT_USB_SS_CAP_SIZE; case GetPortStatus: -- cgit v1.2.3