From: Chunfeng Yun Date: Fri, 4 Dec 2015 13:53:43 +0000 (+0200) Subject: usb: xhci: fix config fail of FS hub behind a HS hub with MTT X-Git-Tag: firefly_0821_release~176^2~570^2~5 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=096b110a3dd3c868e4610937c80d2e3f3357c1a9;p=firefly-linux-kernel-4.4.55.git usb: xhci: fix config fail of FS hub behind a HS hub with MTT if a full speed hub connects to a high speed hub which supports MTT, the MTT field of its slot context will be set to 1 when xHCI driver setups an xHCI virtual device in xhci_setup_addressable_virt_dev(); once usb core fetch its hub descriptor, and need to update the xHC's internal data structures for the device, the HUB field of its slot context will be set to 1 too, meanwhile MTT is also set before, this will cause configure endpoint command fail, so in the case, we should clear MTT to 0 for full speed hub according to section 6.2.2 Signed-off-by: Chunfeng Yun Cc: stable Signed-off-by: Mathias Nyman Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index dfa44d3e8eee..3f912705dcef 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -4778,8 +4778,16 @@ int xhci_update_hub_device(struct usb_hcd *hcd, struct usb_device *hdev, ctrl_ctx->add_flags |= cpu_to_le32(SLOT_FLAG); slot_ctx = xhci_get_slot_ctx(xhci, config_cmd->in_ctx); slot_ctx->dev_info |= cpu_to_le32(DEV_HUB); + /* + * refer to section 6.2.2: MTT should be 0 for full speed hub, + * but it may be already set to 1 when setup an xHCI virtual + * device, so clear it anyway. + */ if (tt->multi) slot_ctx->dev_info |= cpu_to_le32(DEV_MTT); + else if (hdev->speed == USB_SPEED_FULL) + slot_ctx->dev_info &= cpu_to_le32(~DEV_MTT); + if (xhci->hci_version > 0x95) { xhci_dbg(xhci, "xHCI version %x needs hub " "TT think time and number of ports\n",