42 lines
1.6 KiB
Diff
42 lines
1.6 KiB
Diff
From dedd960b894217ae0960a7ac493def9edfa96905 Mon Sep 17 00:00:00 2001
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From: Jonathan Bell <jonathan@raspberrypi.com>
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Date: Wed, 11 Aug 2021 15:33:57 +0100
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Subject: [PATCH] usb: xhci: workaround for bogus SET_DEQ_PENDING
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endpoint state
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See https://github.com/raspberrypi/linux/issues/3981
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An unknown unsafe memory access can result in the ep_state variable
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in xhci_virt_ep being trampled with a stuck SET_DEQ_PENDING state
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despite successful completion of a Set TR Deq Pointer command.
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All URB enqueue/dequeue calls for the endpoint will fail in this state
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so no transfers are possible until the device is reconnected.
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As a workaround, clear the flag if we see it set and issue a new Set
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TR Deq command anyway - this should be harmless, as a prior Set TR Deq
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command will only have been issued in the Stopped state, and if the
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endpoint is Running then the controller is required to ignore it and
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respond with a Context State Error event TRB.
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Signed-off-by: Jonathan Bell <jonathan@raspberrypi.com>
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---
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drivers/usb/host/xhci-ring.c | 6 +++---
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1 file changed, 3 insertions(+), 3 deletions(-)
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--- a/drivers/usb/host/xhci-ring.c
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+++ b/drivers/usb/host/xhci-ring.c
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@@ -4262,9 +4262,9 @@ void xhci_queue_new_dequeue_state(struct
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}
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ep = &xhci->devs[slot_id]->eps[ep_index];
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if ((ep->ep_state & SET_DEQ_PENDING)) {
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- xhci_warn(xhci, "WARN Cannot submit Set TR Deq Ptr\n");
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- xhci_warn(xhci, "A Set TR Deq Ptr command is pending.\n");
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- return;
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+ xhci_warn(xhci, "WARN A Set TR Deq Ptr command is pending for slot %u ep %u\n",
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+ slot_id, ep_index);
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+ ep->ep_state &= ~SET_DEQ_PENDING;
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}
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/* This function gets called from contexts where it cannot sleep */
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