This is a note to let you know that I've just added the patch titled

qmi_wwan: set FLAG_SEND_ZLP to avoid network initiated disconnect

to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: qmi_wwan-set-flag_send_zlp-to-avoid-network-initiated-disconnect.patch and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Thu Mar 22 14:40:24 CET 2018

From: "Bjørn Mork" bjorn@mork.no Date: Thu, 14 Dec 2017 19:55:50 +0100 Subject: qmi_wwan: set FLAG_SEND_ZLP to avoid network initiated disconnect

From: "Bjørn Mork" bjorn@mork.no

[ Upstream commit 245d21190aec547c0de64f70c0e6de871c185a24 ]

It has been reported that the dummy byte we add to avoid ZLPs can be forwarded by the modem to the PGW/GGSN, and that some operators will drop the connection if this happens.

In theory, QMI devices are based on CDC ECM and should as such both support ZLPs and silently ignore the dummy byte. The latter assumption failed. Let's test out the first.

Signed-off-by: Bjørn Mork bjorn@mork.no Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/usb/qmi_wwan.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/net/usb/qmi_wwan.c +++ b/drivers/net/usb/qmi_wwan.c @@ -531,7 +531,7 @@ err:

static const struct driver_info qmi_wwan_info = { .description = "WWAN/QMI device", - .flags = FLAG_WWAN, + .flags = FLAG_WWAN | FLAG_SEND_ZLP, .bind = qmi_wwan_bind, .unbind = qmi_wwan_unbind, .manage_power = qmi_wwan_manage_power, @@ -540,7 +540,7 @@ static const struct driver_info qmi_wwan

static const struct driver_info qmi_wwan_info_quirk_dtr = { .description = "WWAN/QMI device", - .flags = FLAG_WWAN, + .flags = FLAG_WWAN | FLAG_SEND_ZLP, .bind = qmi_wwan_bind, .unbind = qmi_wwan_unbind, .manage_power = qmi_wwan_manage_power,

Patches currently in stable-queue which might be from bjorn@mork.no are

queue-4.9/qmi_wwan-set-flag_send_zlp-to-avoid-network-initiated-disconnect.patch