xhci: handle some XHCI_TRUST_TX_LENGTH quirks cases as default behaviour.

commit 7ff11162808cc2ec66353fc012c58bb449c892c3 upstream.

xhci driver claims it needs XHCI_TRUST_TX_LENGTH quirk for both
Broadcom/Cavium and a Renesas xHC controllers.

The quirk was inteded for handling false "success" complete event for
transfers that had data left untransferred.
These transfers should complete with "short packet" events instead.

In these two new cases the false "success" completion is reported
after a "short packet" if the TD consists of several TRBs.
xHCI specs 4.10.1.1.2 say remaining TRBs should report "short packet"
as well after the first short packet in a TD, but this issue seems so
common it doesn't make sense to add the quirk for all vendors.

Turn these events into short packets automatically instead.

This gets rid of the  "The WARN Successful completion on short TX for
slot 1 ep 1: needs XHCI_TRUST_TX_LENGTH quirk" warning in many cases.

Reported-by: Eli Billauer <eli.billauer@gmail.com>
Reported-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Eli Billauer <eli.billauer@gmail.com>
Tested-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20191211142007.8847-6-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index ae3b2b5fa9f650e9f6cb94b1d513fe817f1d32fc..0d18385f85bb444995e2f1a133c3c20473726a56 100644 (file)
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -2345,7 +2345,8 @@ static int handle_tx_event(struct xhci_hcd *xhci,
        case COMP_SUCCESS:
                if (EVENT_TRB_LEN(le32_to_cpu(event->transfer_len)) == 0)
                        break;
-               if (xhci->quirks & XHCI_TRUST_TX_LENGTH)
+               if (xhci->quirks & XHCI_TRUST_TX_LENGTH ||
+                   ep_ring->last_td_was_short)
                        trb_comp_code = COMP_SHORT_TX;
                else
                        xhci_warn_ratelimited(xhci,