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path: root/drivers/tty/n_gsm.c
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Diffstat (limited to 'drivers/tty/n_gsm.c')
-rw-r--r--drivers/tty/n_gsm.c23
1 files changed, 22 insertions, 1 deletions
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 3b3e1f6632d7..1dbe27c9946c 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -121,6 +121,9 @@ struct gsm_dlci {
struct mutex mutex;
/* Link layer */
+ int mode;
+#define DLCI_MODE_ABM 0 /* Normal Asynchronous Balanced Mode */
+#define DLCI_MODE_ADM 1 /* Asynchronous Disconnected Mode */
spinlock_t lock; /* Protects the internal state */
struct timer_list t1; /* Retransmit timer for SABM and UA */
int retries;
@@ -1364,7 +1367,13 @@ retry:
ctrl->data = data;
ctrl->len = clen;
gsm->pending_cmd = ctrl;
- gsm->cretries = gsm->n2;
+
+ /* If DLCI0 is in ADM mode skip retries, it won't respond */
+ if (gsm->dlci[0]->mode == DLCI_MODE_ADM)
+ gsm->cretries = 1;
+ else
+ gsm->cretries = gsm->n2;
+
mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
gsm_control_transmit(gsm, ctrl);
spin_unlock_irqrestore(&gsm->control_lock, flags);
@@ -1472,6 +1481,7 @@ static void gsm_dlci_t1(struct timer_list *t)
if (debug & 8)
pr_info("DLCI %d opening in ADM mode.\n",
dlci->addr);
+ dlci->mode = DLCI_MODE_ADM;
gsm_dlci_open(dlci);
} else {
gsm_dlci_close(dlci);
@@ -2861,11 +2871,22 @@ 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;
}