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From: Marc SCHAEFER <schaefer@alphanet.ch>
To: kernelnewbies@kernelnewbies.org
Subject: Re: Does sysrq work over USB?
Date: Sun, 21 Nov 2021 16:47:57 +0100	[thread overview]
Message-ID: <20211121154757.GA5318@alphanet.ch> (raw)
In-Reply-To: <YZQinJge6AeJdtdO@valentin-vidic.from.hr>

On Tue, Nov 16, 2021 at 10:29:00PM +0100, Valentin Vidi?? wrote:
> Do you have console=ttyUSB0,... set? What does /proc/consoles say?

No, I did not.

Now, I have added on a test machine:

   console=ttyUSB0,9600 console=tty0

to /etc/default/grub and started upgrade-grub and rebooted.

I had and I still have:

   root@gluster-1:~# cat /proc/consoles 
   tty0                 -WU (EC p  )    4:1

However, the command line seems correct and multiple console= are
valid [1]:

   root@gluster-1:~# cat /proc/cmdline 
   BOOT_IMAGE=/vmlinuz-4.19.0-18-amd64 root=/dev/mapper/vg1-root ro console=ttyUSB0,9600 console=tty0 quiet raid0.default_layout=1

It does not seem to be work for some reason.

Let's try with one ttyUSB console specification only: does not
boot anymore. Does not print anything on ttyUSB0. Had to recover
using a grub kernel command line edition at boot time.

Any idea?

NB: the USB serial port works with cu bidirectionnally once the
system is booted, but %break has no effect.

[1] https://www.kernel.org/doc/html/latest/admin-guide/serial-console.html

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  reply	other threads:[~2021-11-21 15:49 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-16 14:04 Does sysrq work over USB? Marc SCHAEFER
2021-11-16 21:29 ` Valentin Vidić
2021-11-21 15:47   ` Marc SCHAEFER [this message]
2021-11-21 17:51     ` Valentin Vidić
2021-11-21 18:07       ` Valentin Vidić
2021-11-21 20:49         ` Marc SCHAEFER

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