qmi_wwan: set FLAG_SEND_ZLP to avoid network initiated disconnect
authorBjørn Mork <bjorn@mork.no>
Thu, 14 Dec 2017 18:55:50 +0000 (19:55 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sat, 24 Mar 2018 10:01:23 +0000 (11:01 +0100)
commit5ff0741646fd4aad0b9454c2eba5b20d8d82fc56
tree5fd97b9320f8808b25ec4750361b0fe7b1803a0b
parenta9a14b17f72cab586572ad11e3c4c92988d54360
qmi_wwan: set FLAG_SEND_ZLP to avoid network initiated disconnect

[ 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