This is a note to let you know that I've just added the patch titled
tty: n_gsm: fix missing update of modem controls after DLCI open
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tty-n_gsm-fix-missing-update-of-modem-controls-after.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 89a62581ea1dbac20493de0e2927609322683feb
Author: Daniel Starke <daniel.starke@xxxxxxxxxxx>
Date: Wed Apr 20 03:13:44 2022 -0700
tty: n_gsm: fix missing update of modem controls after DLCI open
[ Upstream commit 48473802506d2d6151f59e0e764932b33b53cb3b ]
Currently the peer is not informed about the initial state of the modem
control lines after a new DLCI has been opened.
Fix this by sending the initial modem control line states after DLCI open.
Fixes: e1eaea46bb40 ("tty: n_gsm line discipline")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Daniel Starke <daniel.starke@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20220420101346.3315-1-daniel.starke@xxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index d3d5308daf35..c52d5e0d5c6f 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -371,6 +371,7 @@ static const u8 gsm_fcs8[256] = {
#define GOOD_FCS 0xCF
static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len);
+static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk);
/**
* gsm_fcs_add - update FCS
@@ -1489,6 +1490,9 @@ static void gsm_dlci_open(struct gsm_dlci *dlci)
dlci->state = DLCI_OPEN;
if (debug & 8)
pr_debug("DLCI %d goes open.\n", dlci->addr);
+ /* Send current modem state */
+ if (dlci->addr)
+ gsmtty_modem_update(dlci, 0);
wake_up(&dlci->gsm->event);
}
