diff options
| author | Tony Lindgren <tony@atomide.com> | 2018-04-07 10:19:51 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-05-01 15:13:06 -0700 |
| commit | 5080d3339eaf9eff6765ec99c29bede5df80a360 (patch) | |
| tree | 46775155df0eac675955b9375ac8603407d15131 | |
| parent | 11723a916fb7d7e1b303e0a331e4a8214830a9e4 (diff) | |
| download | linux-rt-5080d3339eaf9eff6765ec99c29bede5df80a360.tar.gz | |
tty: n_gsm: Fix DLCI handling for ADM mode if debug & 2 is not set
commit b2d89ad9c9682e795ed6eeb9ed455789ad6cedf1 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: ea3d8465ab9b ("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: Tony Lindgren <tony@atomide.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/n_gsm.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index f2ba65ba1ef6..9e9016e67843 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -2875,11 +2875,22 @@ static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) static int gsm_carrier_raised(struct tty_port *port) { struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); + struct gsm_mux *gsm = dlci->gsm; + /* Not yet open so no carrier info */ if (dlci->state != DLCI_OPEN) return 0; if (debug & 2) return 1; + + /* + * Basic mode with control channel in ADM mode may not respond + * to CMD_MSC at all and modem_rx is empty. + */ + if (gsm->encoding == 0 && gsm->dlci[0]->mode == DLCI_MODE_ADM && + !dlci->modem_rx) + return 1; + return dlci->modem_rx & TIOCM_CD; } |