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 D684E4F5E18; Wed, 30 Sep 2026 18:38:51 +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=1790793533; cv=none; b=a2ETNylrHUlZcXHTUNDIP/JM2IQwHlKrm3+QYPjVKTZBOsQn60OScwtBkeTx2RrsCIcyTaRmMIY/kRD5VmyP6HCCzVE76SSdCj5VrC5bQZi2vVMO030S7qhu4Um1TAC0baSxnwfNwwSa45sLr8/G7J4/iQhviaQUctHN9CXx330= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790793533; c=relaxed/simple; bh=1jxkCdgPqevviy6cgjfE2fqNHT6cbpLczH53RXzY16o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nhxvcqG9RCnsZ82ShnxvWg+r0dSlWDxT9DbeJDa32kKm5H2DPRzk7eqy22sKr/q527164kM5QSlaIdbyml6prxb0+Y5Qv1n+e5RpNDDrgk0g6ol+ZycMmrZ7nGbtL1bCnxuud5Iv9fk5kVYoBkgDrxn4JgXhK6vXu88ZU9n5xOA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=RPJzc9uv; 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="RPJzc9uv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 335421F00898; Wed, 30 Sep 2026 18:38:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790793531; bh=IoTKdLL6aYJZI5+y77utXr0fYJ7fV1X3lqjRlNNoWYQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=RPJzc9uv1kG47vhoQ0ic/CfbxA59qgA81pJCbILxW69tyHjUu33H/IZCMXNvWj/dS ZAc5cUXG8hQ4rQEsT5F8c+jEde2ZVgmPIPVjiM0oKPjNZmRcdRzfVb1pO3AU4xWGaC Gak4R5Yrjr++YK8Z6fk0Zp9ELVrtNv4WK0vz/Ws0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ming Wang , Jakub Kicinski Subject: [PATCH 6.18 288/395] net: usb: cdc_mbim: add MeiG Smart SRM821 to ZLP whitelist Date: Wed, 30 Sep 2026 17:29:10 +0200 Message-ID: <20260930152346.907090250@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152340.591469096@linuxfoundation.org> References: <20260930152340.591469096@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 6.18-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 @@ -634,6 +634,11 @@ 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