diff mbox series

[19/33] xhci: Fix control transfer error on Etron xHCI host

Message ID 20241106101459.775897-20-mathias.nyman@linux.intel.com (mailing list archive)
State Accepted
Commit 5e1c67abc9301d05130b7e267c204e7005503b33
Headers show
Series xhci features and fixes for usb-next | expand

Commit Message

Mathias Nyman Nov. 6, 2024, 10:14 a.m. UTC 
From: Kuangyi Chiang <ki.chiang65@gmail.com>

Performing a stability stress test on a USB3.0 2.5G ethernet adapter
results in errors like this:

[   91.441469] r8152 2-3:1.0 eth3: get_registers -71
[   91.458659] r8152 2-3:1.0 eth3: get_registers -71
[   91.475911] r8152 2-3:1.0 eth3: get_registers -71
[   91.493203] r8152 2-3:1.0 eth3: get_registers -71
[   91.510421] r8152 2-3:1.0 eth3: get_registers -71

The r8152 driver will periodically issue lots of control-IN requests
to access the status of ethernet adapter hardware registers during
the test.

This happens when the xHCI driver enqueue a control TD (which cross
over the Link TRB between two ring segments, as shown) in the endpoint
zero's transfer ring. Seems the Etron xHCI host can not perform this
TD correctly, causing the USB transfer error occurred, maybe the upper
driver retry that control-IN request can solve problem, but not all
drivers do this.

|     |
-------
| TRB | Setup Stage
-------
| TRB | Link
-------
-------
| TRB | Data Stage
-------
| TRB | Status Stage
-------
|     |

To work around this, the xHCI driver should enqueue a No Op TRB if
next available TRB is the Link TRB in the ring segment, this can
prevent the Setup and Data Stage TRB to be breaked by the Link TRB.

Check if the XHCI_ETRON_HOST quirk flag is set before invoking the
workaround in xhci_queue_ctrl_tx().

Fixes: d0e96f5a71a0 ("USB: xhci: Control transfer support.")
Cc: <stable@vger.kernel.org>
Signed-off-by: Kuangyi Chiang <ki.chiang65@gmail.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
---
 drivers/usb/host/xhci-ring.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
diff mbox series

Patch

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index f62b243d0fc4..517df97ef496 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -3733,6 +3733,20 @@  int xhci_queue_ctrl_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 	if (!urb->setup_packet)
 		return -EINVAL;
 
+	if ((xhci->quirks & XHCI_ETRON_HOST) &&
+	    urb->dev->speed >= USB_SPEED_SUPER) {
+		/*
+		 * If next available TRB is the Link TRB in the ring segment then
+		 * enqueue a No Op TRB, this can prevent the Setup and Data Stage
+		 * TRB to be breaked by the Link TRB.
+		 */
+		if (trb_is_link(ep_ring->enqueue + 1)) {
+			field = TRB_TYPE(TRB_TR_NOOP) | ep_ring->cycle_state;
+			queue_trb(xhci, ep_ring, false, 0, 0,
+					TRB_INTR_TARGET(0), field);
+		}
+	}
+
 	/* 1 TRB for setup, 1 for status */
 	num_trbs = 2;
 	/*