Re: [PATCH] um: change defconfig to stop spawning xterm - richard -rw- weinberger

From: richard -rw- weinberger <richard.weinberger@gmail.com>
To: Richard Weinberger <richard@nod.at>
Cc: Lennart Poettering <mzxreary@0pointer.de>,
	Ramkumar Ramachandra <artagnon@gmail.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: [PATCH] um: change defconfig to stop spawning xterm
Date: Tue, 23 Jul 2013 07:47:07 +0200	[thread overview]
Message-ID: <CAFLxGvx0-TA7R5d6ienSiRm+rrGtCyf_LU5BNTAn1t7U9Ji8Jw@mail.gmail.com> (raw)
In-Reply-To: <51EE1765.2000402@nod.at>

Adding Al again, someone dropped him from the CC list...

On Tue, Jul 23, 2013 at 7:40 AM, Richard Weinberger <richard@nod.at> wrote:
> Lennart,
>
> Am 23.07.2013 00:32, schrieb Lennart Poettering:
>> On Mon, 22.07.13 16:13, Ramkumar Ramachandra (artagnon@gmail.com) wrote:
>>
>>>
>>> [Corrected Lennart's email ID]
>>>
>>> Richard Weinberger wrote:
>>>> CC'ing Lennart.
>>>>
>>>> Am 22.07.2013 11:45, schrieb Ramkumar Ramachandra:
>>>>> Ramkumar Ramachandra wrote:
>>>>>> [1]: http://lists.freedesktop.org/archives/systemd-devel/2013-July/012152.html
>>>>>
>>>>> ... and the patches were rejected.  Lennart says that UML providing
>>>>> /dev/tty* is wrong, and that UML should call them /dev/hvc* (or
>>>>> something).  Can we do something about the situation?  Can we remove
>>>>> /dev/tty*, and provide /dev/hvc*?  Will we be breaking existing users?
>>>>>
>>>>> Thanks.
>>>>>
>>>>> Lennart Poettering wrote:
>>>>>> UML shouldn't be penalized for not implementing some terminal emulation,
>>>>>> but it should be penalized for doing so under the label of "VT support",
>>>>>> which it simply is not providing.
>>>>>>
>>>>>> They can call their ttys any way they want. If the call them
>>>>>> /dev/tty[1..64] however, then they need to implement the VC
>>>>>> interfaces. All of them.
>>>>
>>>> Lennart, can you please explain us why /dev/tty[1..64] is forced to
>>>> have virtual console support?
>>
>> /dev/tty[1..64] is the userspace API to the kernel VT subsystem. If you
>> support it you need to match up all /dev/tty[1..64] with a
>> /dev/vcs[1..64] + /dev/vcsa[1..64]. You need to expose a tty that
>> understands TERM=linux and the ioctls listed on console_ioctl(4). You
>> need /dev/tty0 as something that behaves like a symlink to the fg
>> VT. You should also support files like /sys/class/tty/tty0/active with
>> its POLLHUP iface.
>
> I sightly disagree with you.
> /dev/tty[1..64] is not directly bound to VT.
> You can have systems with CONFIG_VT=n and still have /dev/tty[1..64].
> Linux supports this perfectly.
> UML does not have VT because having virtual consoles makes no sense.
> (Same like on s390)
>
> Thanks,
> //richard
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--
Thanks,
//richard