From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0EE4030CB2B; Wed, 17 Sep 2025 12:45:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758113121; cv=none; b=o37393OyPSuD9FvR2SeyXPqVyiZ+Y3xs61ZshOSPN5AwbtpVB6FJ5Mt0oqsS+jeR4dNvNugsSVybQ8pomU+JKEE0i39F1HlsNIlV0U9Nf5UP0XK5gO8aAWICeVadVwF/qp4/tQwZLZNnwz7lMMyxGKP3fVvGBYDnOPYwEwh/1Gs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758113121; c=relaxed/simple; bh=fz+0LhTTrrIupYF34IGJAfNMi5isLY41Fok6mr08lx0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=A//CmPGK58GzU6mBrkARwbGB8U28rOP0Bp9wNbA6gVkTbpKk4ZhHO5Vr3qTrs2nPdzJzGKSjBQ+f1mjjCO5GSGxapZa9yhGwAqbQoirt0HuiKHfGigl4umavLH9GABjeNw2VjQu7sJvJ6vLy9Xd/uWhUz9S9SrMYnvkZ4IOtbL8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=KuuUUUwy; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="KuuUUUwy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 48213C4CEF0; Wed, 17 Sep 2025 12:45:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1758113120; bh=fz+0LhTTrrIupYF34IGJAfNMi5isLY41Fok6mr08lx0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KuuUUUwyU0fMXYTedPzQi7lcWX64+xzJmchzzqA0/jHLb91yiRBK/gNFHXnWEBwUL 18g5M1qW/pb0oKYIX/RQ5gr/FDvWn/X5FwLbHjUCYBJwbHq00bFdfC6bMXt8PMtt0c ogK7ColO9+S/SJtR0zoaFvfcqYa3U8+IGaxPTs4s= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Mathias Nyman Subject: [PATCH 6.16 178/189] xhci: dbc: Fix full DbC transfer ring after several reconnects Date: Wed, 17 Sep 2025 14:34:48 +0200 Message-ID: <20250917123356.233094513@linuxfoundation.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20250917123351.839989757@linuxfoundation.org> References: <20250917123351.839989757@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mathias Nyman commit a5c98e8b1398534ae1feb6e95e2d3ee5215538ed upstream. Pending requests will be flushed on disconnect, and the corresponding TRBs will be turned into No-op TRBs, which are ignored by the xHC controller once it starts processing the ring. If the USB debug cable repeatedly disconnects before ring is started then the ring will eventually be filled with No-op TRBs. No new transfers can be queued when the ring is full, and driver will print the following error message: "xhci_hcd 0000:00:14.0: failed to queue trbs" This is a normal case for 'in' transfers where TRBs are always enqueued in advance, ready to take on incoming data. If no data arrives, and device is disconnected, then ring dequeue will remain at beginning of the ring while enqueue points to first free TRB after last cancelled No-op TRB. s Solve this by reinitializing the rings when the debug cable disconnects and DbC is leaving the configured state. Clear the whole ring buffer and set enqueue and dequeue to the beginning of ring, and set cycle bit to its initial state. Cc: stable@vger.kernel.org Fixes: dfba2174dc42 ("usb: xhci: Add DbC support in xHCI driver") Signed-off-by: Mathias Nyman Link: https://lore.kernel.org/r/20250902105306.877476-3-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/xhci-dbgcap.c | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-) --- a/drivers/usb/host/xhci-dbgcap.c +++ b/drivers/usb/host/xhci-dbgcap.c @@ -462,6 +462,25 @@ static void xhci_dbc_ring_init(struct xh xhci_initialize_ring_info(ring); } +static int xhci_dbc_reinit_ep_rings(struct xhci_dbc *dbc) +{ + struct xhci_ring *in_ring = dbc->eps[BULK_IN].ring; + struct xhci_ring *out_ring = dbc->eps[BULK_OUT].ring; + + if (!in_ring || !out_ring || !dbc->ctx) { + dev_warn(dbc->dev, "Can't re-init unallocated endpoints\n"); + return -ENODEV; + } + + xhci_dbc_ring_init(in_ring); + xhci_dbc_ring_init(out_ring); + + /* set ep context enqueue, dequeue, and cycle to initial values */ + xhci_dbc_init_ep_contexts(dbc); + + return 0; +} + static struct xhci_ring * xhci_dbc_ring_alloc(struct device *dev, enum xhci_ring_type type, gfp_t flags) { @@ -885,7 +904,7 @@ static enum evtreturn xhci_dbc_do_handle dev_info(dbc->dev, "DbC cable unplugged\n"); dbc->state = DS_ENABLED; xhci_dbc_flush_requests(dbc); - + xhci_dbc_reinit_ep_rings(dbc); return EVT_DISC; } @@ -895,7 +914,7 @@ static enum evtreturn xhci_dbc_do_handle writel(portsc, &dbc->regs->portsc); dbc->state = DS_ENABLED; xhci_dbc_flush_requests(dbc); - + xhci_dbc_reinit_ep_rings(dbc); return EVT_DISC; }