From: sashiko-bot@kernel.org
To: "Jie Deng" <dengjie03@kylinos.cn>
Cc: linux-usb@vger.kernel.org
Subject: Re: [PATCH] usb: xhci: Add XHCI_TT_SOFT_RETRY quirk for transaction errors on TT devices
Date: Sat, 10 Oct 2026 03:32:13 +0000 [thread overview]
Message-ID: <sashiko-outbox-166247@kernel.org> (raw)
In-Reply-To: <20261010032518.2040608-1-dengjie03@kylinos.cn>
> Low-speed devices behind a high-speed hub on some xHCI controllers stop
> working after repeated lsusb -v: a transient USB transaction error on a
> bulk/interrupt endpoint is followed by a hard reset recovery where every
> command completes successfully (Reset EP with TSP=0 and Set TR Deq both
> return COMP_SUCCESS), but the first new split transaction issued after
> the restart fails again. After two such cycles the hub reports a port
> connection change and the device drops off.
>
> The affected silicon does not honor the xHCI spec (4.6.8) requirement
> that a Reset Endpoint command with TSP=0 "reset any USB2 split
> transaction state associated with the endpoint": the stale split state
> survives the reset, so the next split transaction carries the old
> transaction's identity and can never match the hub TT state, cleared
> or not. The soft reset path (TSP=1), which per the spec maintains the
> split transaction state and retries the last transaction on the next
> [ ... ]
> On the affected controller every error reports comp code 4 (USB
> Transaction Error), tt_info 0x301 and err_count 1, i.e. each in-place
> retry succeeds immediately and the fallback is never taken.
>
> Signed-off-by: Jie Deng <dengjie03@kylinos.cn>
Sashiko has reviewed this patch and found no issues. It looks great!
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261010032518.2040608-1-dengjie03@kylinos.cn?part=1
next prev parent reply other threads:[~2026-10-10 3:32 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-10 3:25 [PATCH] usb: xhci: Add XHCI_TT_SOFT_RETRY quirk for transaction errors on TT devices Jie Deng
2026-10-10 3:32 ` sashiko-bot [this message]
2026-10-10 5:52 ` Michal Pecio
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