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=1794060898; b=algCKTW+2s/RBTcT2mFt+nqcA+SCPNJ6JO2fBmeobJYJT0yQ+nU7YokWEEtkx14Lw0P1 nCuav/PzLPdrJz6A4Rqeq+FVUzv354S2XKgoBkqgNdas/O7ML8jEweRuFjvm9L3UtHH8q lklIrDzamUJinGRc49bMW81Fq7p650wyMRHkMClLgKmxjJdkSuvfZuqIhk89z0F3l9ACB EMEGg7cIfTVUafVEwRDSKDO6Escjb2Ebs43DBO1Oz3liednwFL+SunM1iMqEAczj4LenK im9LU+KBKy7FNatrtTAq1vUFregLPbtCr4h6wHJIp+5jrd0nK/LW64cI/knS4TOJVYQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794060898; 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=wjG5ux0YCgMXTFogWk3LN+N9nCwNwn0K4wilkTuOP6I=; b=q5GnUefyKOU3+jVal21fdughKBBWCuPkHw0Jfh0MgPQsdeTmQd0XlD+0n2zlDyWF988t FtsOA74IyhxqRorr9Ne70rsaIKLYW6WbbDYx4WrAfoID/d+Mtcr6e1fXgGomqHc8kDtmM YEhWaO8tozxDlwx7ivT1U27SRHO8Cq2I4/EsryDHya4r9LzuYrobrUV8kHKyZinAynEGc Nsdur6FXWxF8wMCDJj/o3u77SsiXM4VWkZaOmntNa669i67yO0d5+bky11lRv6LTqQj2E IYRtToXoqgtOO5TnhYinZHxWm0L4tXdWHqKTkw738k+uB6AT2yv8OCMPZpNrJWHZNDw== 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="dRY5yb/E"; 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 EB802606A338; Sat, 7 Nov 2026 14:14:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=dRY5yb/E Received: by smtp.kernel.org (Postfix) with ESMTPSA id 954521F0089F; Sat, 7 Nov 2026 14:14:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794060897; bh=wjG5ux0YCgMXTFogWk3LN+N9nCwNwn0K4wilkTuOP6I=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=dRY5yb/E0WYCcAkwxfOAFJpowd3MPQPDX3iRk2ChNSOfWs2qxyGs2jfnWLZ3CImna 4YEoecGTXPoi2d2o7A2VKbPPHGIdqhoH0ZD4RVWMAHYNdAH6gAZmeJ460PjXBc4Kw/ Xqf6eL+lva6eB8gH3B3uxZtQ47nbCc0f102qVldo= 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 6.12 0272/1536] net: usb: cdc_ether: add quirk for AMI BMC stale link events Date: Sat, 7 Nov 2026 08:38:08 -0500 Message-ID: <20261107135005.316323644@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134957.653319350@linuxfoundation.org> References: <20261107134957.653319350@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org 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 6.12-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