n_gsm: Send CLD command on exit

A DISC on DLCI 0 should close down the mux but Michael Lauer reports this
is not the case for some modems. Send a CLD as well.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Tested-by: Michael Lauer
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index ed42908..8d7766b 100644 (file)
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -2003,6 +2003,7 @@ void gsm_cleanup_mux(struct gsm_mux *gsm)
        int i;
        struct gsm_dlci *dlci = gsm->dlci[0];
        struct gsm_msg *txq;
+       struct gsm_control *gc;
 
        gsm->dead = 1;
 
@@ -2016,6 +2017,13 @@ void gsm_cleanup_mux(struct gsm_mux *gsm)
        spin_unlock(&gsm_mux_lock);
        WARN_ON(i == MAX_MUX);
 
+       /* In theory disconnecting DLCI 0 is sufficient but for some
+          modems this is apparently not the case. */
+       if (dlci) {
+               gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
+               if (gc)
+                       gsm_control_wait(gsm, gc);
+       }
        del_timer_sync(&gsm->t2_timer);
        /* Now we are sure T2 has stopped */
        if (dlci) {