net: usb: cdc_mbim: add MeiG Smart SRM821 to ZLP whitelist

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 <wangming01@loongson.cn>
Link: https://patch.msgid.link/20260920074500.826121-1-wangming01@loongson.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

0 files changed, 0 insertions, 0 deletions