From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 79F754E01FA; Wed, 30 Sep 2026 15:59:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790783954; cv=none; b=Pvk7ZZOtqtnzya+QCKn0RbhXl8mD/UYqvG6HJiHB5h8bUxWycjceBXa4p9ceQ024YtbiklLwVjVzjNlZ1SNCalDVpUd9OV3wu46s9gTY7qzOIV/esXXYj99joVs9QtURE3UG7GUye5hBMimHLL0wu0XShf3Ki4jllziAoWcBkpM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790783954; c=relaxed/simple; bh=gVcDVO8JLkzBbFi7TGy/Ht8jk0izFaZojdg+2CJ977Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=WpanGJPLTw8TsrMNTyaSl3hbheKYq4QSSgcpj+qFzdXObgRuh1Il+ls5vdDkzPuKULae+dHxOhw1RixoxSqorutFBhmH5z5LGzgW/g6maH7Mhs8+8lSWQCkrFkegjD7dxcwGed62J4U3ipyUQATqWD+Oo1j6Y8ebyTMbmyQdzrk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=OxAaHe/Z; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="OxAaHe/Z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7949D1F00893; Wed, 30 Sep 2026 15:59:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790783952; bh=FfHvAE3ZhPX6xBYlJ7BNDqM5kulTdKYqDq6+u2/g4gU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=OxAaHe/ZMPdRFR0qIxq7QXaK1SOi0N+bQ9Y8Qy3Gr6njQMs1Ve1KYKqEE5uMmNtLx w38NMkY+HrM5SaetB3FQqqjgskVkhPqM9hQhihDWEEklVyCeUOk94vMLOrm5Qgkao0 RSeiG5391l6BNfbi1CPHP4yQj/8wkIC1tbII5+N4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ming Wang , Jakub Kicinski Subject: [PATCH 5.10 579/595] net: usb: cdc_mbim: add MeiG Smart SRM821 to ZLP whitelist Date: Wed, 30 Sep 2026 17:27:52 +0200 Message-ID: <20260930152400.187324198@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152347.700140858@linuxfoundation.org> References: <20260930152347.700140858@linuxfoundation.org> User-Agent: quilt/0.69 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 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ming Wang commit f75f21ef36285e5f56ee0c428bd2909ee81165b9 upstream. The MeiG Smart SRM821 5G module (0x2dee:0x4d53) crashes and drops off the USB bus when it receives a Zero Length Packet (ZLP) after sending or receiving an NTB of exactly 16384 bytes (tx_max). According to the MBIM specification, devices do not require a ZLP if the NTB size is exactly dwNtbOutMaxSize. However, the cdc_mbim driver defaults to sending ZLPs for devices not explicitly whitelisted to accommodate non-conformant hardware. This default behavior breaks the strictly conformant MeiG SRM821 module. Add this device to the ZLP conformance whitelist (cdc_mbim_info) so the driver will pad the NTB to avoid sending ZLPs, preventing the device firmware from crashing. Cc: stable@vger.kernel.org Signed-off-by: Ming Wang Link: https://patch.msgid.link/20260920074500.826121-1-wangming01@loongson.cn Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- drivers/net/usb/cdc_mbim.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/drivers/net/usb/cdc_mbim.c +++ b/drivers/net/usb/cdc_mbim.c @@ -632,6 +632,11 @@ static const struct usb_device_id mbim_d .driver_info = (unsigned long)&cdc_mbim_info, }, + /* MeiG Smart SRM821 ZLP conformance */ + { USB_DEVICE_AND_INTERFACE_INFO(0x2dee, 0x4d53, USB_CLASS_COMM, USB_CDC_SUBCLASS_MBIM, USB_CDC_PROTO_NONE), + .driver_info = (unsigned long)&cdc_mbim_info, + }, + /* Some Huawei devices, ME906s-158 (12d1:15c1) and E3372 * (12d1:157d), are known to fail unless the NDP is placed * after the IP packets. Applying the quirk to all Huawei