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Message-Id: <20160127180936.526628272@linuxfoundation.org>
Date: Wed, 27 Jan 2016 10:12:23 -0800
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Chunfeng Yun <chunfeng.yun@...iatek.com>,
Mathias Nyman <mathias.nyman@...ux.intel.com>
Subject: [PATCH 4.3 076/157] usb: xhci: fix config fail of FS hub behind a HS hub with MTT
4.3-stable review patch. If anyone has any objections, please let me know.
------------------
From: Chunfeng Yun <chunfeng.yun@...iatek.com>
commit 096b110a3dd3c868e4610937c80d2e3f3357c1a9 upstream.
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 <chunfeng.yun@...iatek.com>
Signed-off-by: Mathias Nyman <mathias.nyman@...ux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
drivers/usb/host/xhci.c | 8 ++++++++
1 file changed, 8 insertions(+)
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -4778,8 +4778,16 @@ int xhci_update_hub_device(struct usb_hc
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",
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