* ttyACM and BREAK chars ?
@ 2019-09-11 12:39 Joakim Tjernlund
2019-09-11 14:22 ` Oliver Neukum
0 siblings, 1 reply; 6+ messages in thread
From: Joakim Tjernlund @ 2019-09-11 12:39 UTC (permalink / raw)
To: linux-usb
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 ?
if so, could it be added ?
Jocke
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: ttyACM and BREAK chars ?
2019-09-11 12:39 ttyACM and BREAK chars ? Joakim Tjernlund
@ 2019-09-11 14:22 ` Oliver Neukum
2019-09-11 14:34 ` Joakim Tjernlund
0 siblings, 1 reply; 6+ messages in thread
From: Oliver Neukum @ 2019-09-11 14:22 UTC (permalink / raw)
To: Joakim Tjernlund, linux-usb
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.
But the support is optional in ACM devices.
What is bmCapabilities in sysfs for your device?
Regards
Oliver
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: ttyACM and BREAK chars ?
2019-09-11 14:22 ` Oliver Neukum
@ 2019-09-11 14:34 ` Joakim Tjernlund
2019-09-11 18:27 ` Oliver Neukum
0 siblings, 1 reply; 6+ messages in thread
From: Joakim Tjernlund @ 2019-09-11 14:34 UTC (permalink / raw)
To: oneukum, linux-usb
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
> But the support is optional in ACM devices.
>
> What is bmCapabilities in sysfs for your device?
I found one bmCapabilities in sysfs:
cat /sys/devices/pci0000:00/0000:00:14.0/usb1/1-6/1-6.3/1-6.3:1.1/bmCapabilities
2
Locks like my device
Jocke
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: ttyACM and BREAK chars ?
2019-09-11 14:34 ` Joakim Tjernlund
@ 2019-09-11 18:27 ` Oliver Neukum
2019-09-12 7:09 ` Joakim Tjernlund
0 siblings, 1 reply; 6+ messages in thread
From: Oliver Neukum @ 2019-09-11 18:27 UTC (permalink / raw)
To: Joakim Tjernlund, linux-usb
[-- Attachment #1: Type: text/plain, Size: 978 bytes --]
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
[-- Attachment #2: 0001-cdc-acm-fix-BREAK-rx-code-path-adding-necessary-call.patch --]
[-- Type: text/x-patch, Size: 1095 bytes --]
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
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: ttyACM and BREAK chars ?
2019-09-11 18:27 ` Oliver Neukum
@ 2019-09-12 7:09 ` Joakim Tjernlund
2019-09-12 8:30 ` Oliver Neukum
0 siblings, 1 reply; 6+ messages in thread
From: Joakim Tjernlund @ 2019-09-12 7:09 UTC (permalink / raw)
To: oneukum, linux-usb
On Wed, 2019-09-11 at 20:27 +0200, Oliver Neukum wrote:
> 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?
>
Sure, I can test it but from looking at the patch it seems like ACM already ignores
BREAKs(hardcoded) and with your patch you actually start reporting them.
My problem is sudden disconnects I cannot explain but I think they are connect to BREAKs
I have seen these errors in dmesg though, not sure if they help the diagnose:
[181780.167987] usb usb1-port6: disabled by hub (EMI?), re-enabling...
[181780.168208] cdc_acm 1-6.3:1.1: acm_ctrl_irq - usb_submit_urb failed: -19
[181780.167996] usb 1-6: USB disconnect, device number 30
[181780.176548] usb 1-6-port2: attempt power cycle
[181781.772847] usb 1-6.3: USB disconnect, device number 32
[181781.773134] cdc_acm 1-6.3:1.1: failed to set dtr/rts
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: ttyACM and BREAK chars ?
2019-09-12 7:09 ` Joakim Tjernlund
@ 2019-09-12 8:30 ` Oliver Neukum
0 siblings, 0 replies; 6+ messages in thread
From: Oliver Neukum @ 2019-09-12 8:30 UTC (permalink / raw)
To: Joakim Tjernlund, linux-usb
Am Donnerstag, den 12.09.2019, 07:09 +0000 schrieb Joakim Tjernlund:
> On Wed, 2019-09-11 at 20:27 +0200, Oliver Neukum wrote:
> > 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?
> >
>
> Sure, I can test it but from looking at the patch it seems like ACM already ignores
> BREAKs(hardcoded) and with your patch you actually start reporting them.
Well, what is not reported cannot really be ignored.
AFAICT n_tty_receive_break() should solve the issue generically.
> My problem is sudden disconnects I cannot explain but I think they are connect to BREAKs
> I have seen these errors in dmesg though, not sure if they help the diagnose:
> [181780.167987] usb usb1-port6: disabled by hub (EMI?), re-enabling...
The relevant fault happens likely just before that.
> [181780.168208] cdc_acm 1-6.3:1.1: acm_ctrl_irq - usb_submit_urb failed: -19
> [181780.167996] usb 1-6: USB disconnect, device number 30
> [181780.176548] usb 1-6-port2: attempt power cycle
> [181781.772847] usb 1-6.3: USB disconnect, device number 32
> [181781.773134] cdc_acm 1-6.3:1.1: failed to set dtr/rts
Either your cabling is indeed crap, or something crashes your device.
Regards
Oliver
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2019-09-12 8:45 UTC | newest]
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2019-09-11 12:39 ttyACM and BREAK chars ? Joakim Tjernlund
2019-09-11 14:22 ` Oliver Neukum
2019-09-11 14:34 ` Joakim Tjernlund
2019-09-11 18:27 ` Oliver Neukum
2019-09-12 7:09 ` Joakim Tjernlund
2019-09-12 8:30 ` Oliver Neukum
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