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 24D9251B16C; Wed, 30 Sep 2026 18:23:53 +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=1790792634; cv=none; b=mGvQfvqEGoe2IvgEGr4FMSH33XstlV5+7u8XYngeuB4aMi3Z9qJElYEHoD6WY2tzfxJUC5t79LxYKc+UoHgqlZuUouEvoHcY+t9/4hJD4ADsoBEnjVw0Qoq5DJ+EGWKh6GkAGnVk+0UDokhfWudntG40/hcPwso3viEDNgCfwzc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790792634; c=relaxed/simple; bh=w/12m1h6b33cwhOf+lvXaoKlkXuyk5VwHPdvo0D0pgk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=rRSgFg/CPxWMo6xehl9ep383bdP6AZj14ETQj7hFay/trk8VTzytINW4rswsHgq3BNqIp6jnHkGVKcwkVLjFlXlP6kmYc1IBs7AP6MwqpmSMDUhfL1XnqZQ0mC4fVy2wVJsfOE/cSTURw1GBpcJkuQV5ph2Sdn85gLZY4v8N1RU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=IbF99Ze1; 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="IbF99Ze1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7EE8E1F000FF; Wed, 30 Sep 2026 18:23:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790792633; bh=cTgn1GESVZNj07J6Y4LPjchdtRrGzxN/X4vitDrAsI4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=IbF99Ze1WTeEljTyzIiiiUxpG2FNvyzuzkOOmF9cSebj9MwRw3c5GYFjFCZbNRDIM LVN3jcs7kWs4dGUQRTFwO9BBVNS6nQ9LAwgJwmJwjZN4ttwNfGSl8/6x99QdGnwATH KTHRAE2GVJuTKj6MYt1bfhE4ujPy79WKkpd4XuSI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ming Wang , Jakub Kicinski Subject: [PATCH 5.15 724/752] net: usb: cdc_mbim: add MeiG Smart SRM821 to ZLP whitelist Date: Wed, 30 Sep 2026 17:29:54 +0200 Message-ID: <20260930152413.886454008@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152358.131179731@linuxfoundation.org> References: <20260930152358.131179731@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 5.15-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 @@ -633,6 +633,11 @@ 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