• Tony Lindgren's avatar
    tty: n_gsm: Fix DLCI handling for ADM mode if debug & 2 is not set · 5080d333
    Tony Lindgren authored
    commit b2d89ad9 upstream.
    
    At least on droid 4 with control channel in ADM mode, there is no response
    to Modem Status Command (MSC). Currently gsmtty_modem_update() expects to
    have data in dlci->modem_rx unless debug & 2 is set. This means that on
    droid 4, things only work if debug & 2 is set.
    
    Let's fix the issue by ignoring empty dlci->modem_rx for ADM mode. In
    the AMD mode, CMD_MSC will never respond and gsm_process_modem() won't
    get called to set dlci->modem_rx.
    
    And according to ts_127010v140000p.pdf, MSC is only relevant if basic
    option is chosen, so let's test for that too.
    
    Fixes: ea3d8465 ("tty: n_gsm: Allow ADM response in addition to UA for control dlci")
    Cc: linux-serial@vger.kernel.org
    Cc: Alan Cox <alan@llwyncelyn.cymru>
    Cc: Dan Williams <dcbw@redhat.com>
    Cc: Jiri Prchal <jiri.prchal@aksignal.cz>
    Cc: Jiri Slaby <jslaby@suse.cz>
    Cc: Marcel Partap <mpartap@gmx.net>
    Cc: Merlijn Wajer <merlijn@wizzup.org>
    Cc: Michael Nazzareno Trimarchi <michael@amarulasolutions.com>
    Cc: Michael Scott <michael.scott@linaro.org>
    Cc: Pavel Machek <pavel@ucw.cz>
    Cc: Peter Hurley <peter@hurleysoftware.com>
    Cc: Russ Gorby <russ.gorby@intel.com>
    Cc: Sascha Hauer <s.hauer@pengutronix.de>
    Cc: Sebastian Reichel <sre@kernel.org>
    Signed-off-by: default avatarTony Lindgren <tony@atomide.com>
    Cc: stable <stable@vger.kernel.org>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    5080d333
n_gsm.c 79.4 KB