From: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
To: Ulf Samuelsson <linux-kernel@emagii.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: RFC: mcu_tty: Trying to open /dev/ttyUSB0 and lock access from a kernel driver
Date: Tue, 26 Sep 2017 00:05:16 +0100 [thread overview]
Message-ID: <20170926000516.7b556e58@alans-desktop> (raw)
In-Reply-To: <ed0f000c-acd2-857c-2e6e-e25f72ae9f9e@emagii.com>
On Mon, 25 Sep 2017 15:01:13 +0200
Ulf Samuelsson <linux-kernel@emagii.com> wrote:
> Trying to open /dev/ttyUSB from a kernel driver (which works), but
> locking the
> serial port so noone else can access it does not work.
> Any advice would be appreciated.
File locks are advisory only.
For the rest of it you might want to take a look at how the gsm mux
driver works (the protocol stuff is scary but you can ignore that end).
It plugs a line discipline into a tty and that muxes out as a collection
of ttys and shows how it's meant to be done.
That also means you have an owning process with the port open that can do
locking on it and/or route any raw read/writes to the master port into
the bit bucket.
Alan
prev parent reply other threads:[~2017-09-25 23:05 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-25 13:01 RFC: mcu_tty: Trying to open /dev/ttyUSB0 and lock access from a kernel driver Ulf Samuelsson
2017-09-25 23:05 ` Alan Cox [this message]
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