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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Paul Menzel <pmenzel@molgen.mpg.de>
Cc: linux-serial@vger.kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Donald Buczek <buczek@molgen.mpg.de>
Subject: Re: Device to write to all (serial) consoles
Date: Fri, 2 Aug 2019 18:02:43 +0200	[thread overview]
Message-ID: <20190802160243.GA15484@kroah.com> (raw)
In-Reply-To: <32c2d26f-ec4a-b9a6-b42c-07b27f99ea28@molgen.mpg.de>

On Fri, Aug 02, 2019 at 03:23:08PM +0200, Paul Menzel wrote:
> Dear Linux folks,
> 
> 
> On a lot of devices, like servers, you have more than one serial console,
> and you do not always know, how they are numbered. Therefore, we start a
> console on ttyS0 and ttyS1.
> 
> In user space, we also would like to write to both consoles to not worry
> about the numbering. Writing to `/dev/console` only write to the active
> console.

So the same data to multiple console devices with just one userspace
call?  Why?

>     $ more /proc/consoles # I think
>     tty0                 -WU (EC p  )    4:1
>     ttyS0                -W- (E  p a)    4:65
>     ttyS1                -W- (E  p a)    4:65
> 
> Does a device exist, or can a device be configured so you can write to
> all (serial) consoles from user space?

With one syscall, not that I know of, sorry.

greg k-h

  reply	other threads:[~2019-08-02 16:02 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-02 13:23 Device to write to all (serial) consoles Paul Menzel
2019-08-02 16:02 ` Greg Kroah-Hartman [this message]
2019-08-02 19:59   ` Paul Menzel
2019-08-03  6:46     ` Greg Kroah-Hartman
2019-08-03 13:23     ` Adam Borowski
2019-08-03 13:55       ` Greg Kroah-Hartman
2019-08-03 15:15         ` Adam Borowski
2019-08-08 14:52 ` Enrico Weigelt, metux IT consult

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