From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793829766; b=pGaLqPhytCnD9YOGnvmFu+Zi8G0nbjmL1DR2ziOPQPT53kMe95bCAoMSKiPX2RjHz8E5 cY9ggho9YCtgOihPY6NDJsN6Bpg2b7lHGd+IfBZvJo/W3Hrc6LneAqfhOqolbDDKIHXSZ 8PdeTKANVgbxzQvKD/zASDzzvrM880WIafmFWhJ0KMaXWFDLHW+qEUvZgGjejKHj4o8PE vkQbyZn9TA9Vep6EOQCqzBZTRRr9HZnIZnPiOZ3cmylHvk9yp6s3enerEsJM4wG4N1LPN 49Lqb3y8yzgSDckSVTRyt588c48DqXdxxBZSiGMy41K9IupxRi3+mWoRUlVzI17TjkQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793829766; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=Vm0L1EgorBfigTqU/MQ2OLOeygldfl156nKCddnbLSY=; b=NXYldndO4PY1LKEiLbcQHCj0v7qmtKEimWnCduugHZuCUtxYUcM4QzyUQ1g2ZKEwQdkA PCVaOXw8o3YzSSCyBE3I/pw6W7+hd/+mvVVd9fwDU7qqP6X/gdYSEPeAorFQoQpuaanfs mC4G5hZ6nbijXOkyX9t2KaTvHjEc20nPcFzESo0ARvE+RMZEdRuKyr7FTlgQzzByn3HcY fvM0I+F3hOCOqDKeiAD55rE0lZDmlKL/yEadI7c+hG8inM0HtAbPcLWcLfufZ9+jqPthG QxIki540USitzCWlQgm3XW9Ie9qhaqEr5566DAG7RHj8KXJxtPljRCCBu4A8mzXnsnA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=akqyhVzq; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 74127606C927; Wed, 4 Nov 2026 22:02:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=akqyhVzq Received: by smtp.kernel.org (Postfix) with ESMTPSA id ED6C21F000C1; Wed, 4 Nov 2026 22:02:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793829766; bh=Vm0L1EgorBfigTqU/MQ2OLOeygldfl156nKCddnbLSY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=akqyhVzq374gHWu6cASV/7Ps/Y+aHJuhfOhzQhtJsAxHFlNCjd5w0F9DwcQOK6Edz mLJbfRW7Cs4pEZxRR69jiLEGp6J0Zp1Lmpy+UjhN/dLzITJ+OaJZeldNCPFLDG2GVu fOT8itZw9QRRqF93Jg8r8TnXxLVqqytoQKkvwaeI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jinhui Guo , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.18 0328/1005] net: usb: cdc_ether: add quirk for AMI BMC stale link events Date: Wed, 4 Nov 2026 16:01:01 -0500 Message-ID: <20261104211053.139974323@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211043.516122098@linuxfoundation.org> References: <20261104211043.516122098@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jinhui Guo [ Upstream commit 089ca284afb0f3b2870a5ce41524cbc91ed350d4 ] On AMD Genoa/Turin platforms the BMC-provided USB-Ethernet gadget (American Megatrends, VID 0x046b PID 0xffb0) intermittently fails to respond to ARP after AC cold boot. usbmon captures a stale NETWORK_CONNECTION(off) immediately followed by NETWORK_CONNECTION(on) on the interrupt endpoint (~130us apart) after enumeration. Because alloc_netdev() leaves __LINK_STATE_NOCARRIER cleared, netif_carrier_ok() returns true when the spurious OFF arrives, so usbnet_cdc_status() cannot recognise it as redundant and schedules EVENT_LINK_CHANGE. __handle_link_change() then calls unlink_urbs(), killing ~60 rx URBs whose payload has already been DMA'd into memory — xHCI trace confirms them completing as -ECONNRESET with non-zero residual length. rx_complete() drops these unconditionally. The following ON restores the carrier and re-submits URBs, but the ARP reply is already lost; the interface looks "up but silent" until ifdown/ifup. Fix this by adding a device-specific quirk with FLAG_LINK_INTR set, which makes usbnet_probe() call netif_carrier_off() after bind. With initial carrier == OFF, usbnet_cdc_status() recognises the spurious OFF as matching the current state and drops it; the subsequent ON is the first real event and brings the link up cleanly without ever tearing down the rx queue. The scheduled link-change kevent is harmless because EVENT_DEV_OPEN is not yet set at probe time. This is applied as a device-specific quirk rather than a change to the shared cdc_info driver_info because some CDC devices never send NETWORK_CONNECTION notifications; forcing carrier off for them would leave the link permanently DOWN. Restricting the change to this VID/PID keeps that class of device untouched. Tested on Genoa and Turin across 100+ AC cold boot cycles; ping first-packet success rate went from intermittent to 100%. Signed-off-by: Jinhui Guo Link: https://patch.msgid.link/20260730051341.24930-1-guojinhui.liam@bytedance.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/usb/cdc_ether.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/drivers/net/usb/cdc_ether.c b/drivers/net/usb/cdc_ether.c index a032c1ded4063..05e625a461b49 100644 --- a/drivers/net/usb/cdc_ether.c +++ b/drivers/net/usb/cdc_ether.c @@ -532,6 +532,16 @@ static const struct driver_info cdc_info = { .manage_power = usbnet_manage_power, }; +static const struct driver_info ami_bmc_info = { + .description = "AMI BMC USB Ethernet", + .flags = FLAG_ETHER | FLAG_POINTTOPOINT | FLAG_LINK_INTR, + .bind = usbnet_cdc_bind, + .unbind = usbnet_cdc_unbind, + .status = usbnet_cdc_status, + .set_rx_mode = usbnet_cdc_update_filter, + .manage_power = usbnet_manage_power, +}; + static const struct driver_info zte_cdc_info = { .description = "ZTE CDC Ethernet Device", .flags = FLAG_ETHER | FLAG_POINTTOPOINT, @@ -940,6 +950,12 @@ static const struct usb_device_id products[] = { USB_CDC_SUBCLASS_ETHERNET, USB_CDC_PROTO_NONE), .driver_info = (unsigned long)&wwan_info, +}, { + /* AMI BMC gadget */ + USB_DEVICE_AND_INTERFACE_INFO(0x046b, 0xffb0, USB_CLASS_COMM, + USB_CDC_SUBCLASS_ETHERNET, + USB_CDC_PROTO_NONE), + .driver_info = (unsigned long)&ami_bmc_info, }, { USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ETHERNET, USB_CDC_PROTO_NONE), -- 2.53.0