Re: ttyACM and BREAK chars ?

[Oliver Neukum <oneukum@suse.com>]

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Am Mittwoch, den 11.09.2019, 14:34 +0000 schrieb Joakim Tjernlund:
> On Wed, 2019-09-11 at 16:22 +0200, Oliver Neukum wrote:
> > CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe.
> > 
> > 
> > Am Mittwoch, den 11.09.2019, 12:39 +0000 schrieb Joakim Tjernlund:
> > > Every now and then my ttyACM0 hangs up or sends a BREAK char to my device.
> > > I am trying to make ttyACM ignore incoming(over USB) and not emit
> > > any BREAK automatically using termios (IGN_BRK) but that does not make a difference.
> > > 
> > > Is BREAK handling unimpl. in ttyACM ?
> > 
> > acm_send_break() implements it.
> 
> Yes, I se that funktion but I don't see how one can ignore received BREAKs
> If I set IGN_BRK on /dev/ttyACM0 I expect that every BREAK should just be ignored

Handling breaks looks a bit broken on CDC-ACM.
Could you test the attached patch?

	Regards
		Oliver

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From 74a16a0fdc056659b0543ec377b51fa231a423c2 Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oneukum@suse.com>
Date: Wed, 11 Sep 2019 20:17:38 +0200
Subject: [PATCH] cdc-acm: fix BREAK rx code path adding necessary calls

Counting break events is nice but we should actually report them to
the tty layer.

Fixes: 5a6a62bdb9257 ("cdc-acm: add TIOCMIWAIT")
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/usb/class/cdc-acm.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 62f4fb9b362f..89d97d9763b0 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -312,8 +312,10 @@ static void acm_process_notification(struct acm *acm, unsigned char *buf)
 			acm->iocount.dsr++;
 		if (difference & ACM_CTRL_DCD)
 			acm->iocount.dcd++;
-		if (newctrl & ACM_CTRL_BRK)
+		if (newctrl & ACM_CTRL_BRK) {
 			acm->iocount.brk++;
+			tty_insert_flip_char(&acm->port, 0, TTY_BREAK);
+		}
 		if (newctrl & ACM_CTRL_RI)
 			acm->iocount.rng++;
 		if (newctrl & ACM_CTRL_FRAMING)
-- 
2.16.4