Message-ID: <465B0BC9.2040502@imap.cc>
Date: Mon, 28 May 2007 19:05:13 +0200
From: Tilman Schmidt <tilman@imap.cc>
Organization: me - organized??
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To: "Lars K.W. Gohlke" <lkwg82@gmx.de>
CC: Jan Engelhardt <jengelh@linux01.gwdg.de>, linux-kernel@vger.kernel.org
Subject: Re: How to access correctly serial port inside module?
References: <46485D84.1010902@gmx.de> <46489EF1.2020509@gmx.de> <Pine.LNX.4.61.0705142158340.9570@yvahk01.tjqt.qr> <4648E9F7.5090908@imap.cc> <Pine.LNX.4.61.0705151020310.9570@yvahk01.tjqt.qr> <46536C0F.50101@imap.cc> <4655676A.1000102@gmx.de> <4655C554.7030000@imap.cc> <4655C93D.40005@gmx.de> <Pine.LNX.4.61.0705241927410.31549@yvahk01.tjqt.qr> <4655E463.7000201@gmx.de>
In-Reply-To: <4655E463.7000201@gmx.de>
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Am 24.05.2007 21:15 schrieb Lars K.W. Gohlke:
> Jan Engelhardt schrieb:
[code proposal]
>> [I've warned about it... ;-) ]
>=20
> is it the way to access from kernelspace the userspace fs?
> the not-correct-way?

Yes, indeed.

> If it is so, I will wait for another solution ;)

I'm not sure waiting will help. The roasted pigeons will not come
flying into your mouth.

The possible solutions have been sketched out for you:

a) open the device file from the kernel (described by Jan):
   actively discouraged by the kernelnewbies.org FAQ document,
   and probably won't even work IMHO

b) program the serial port directly (described by Jan):
   will work only with one type of hardware and you'll have to
   disable the regular serial driver first; frowned upon by kernel
   gurus as "reinventing the wheel"

c) abuse the line discipline interface (described by me):
   moderately well documented, and there's precedent for using it
   that way in the well-accepted PPP module as well as my humble
   contribution, the ser_gigaset driver; requires a userspace
   daemon for pushing the line discipline module on the serial
   port and keeping it there

d) use the serio interface (described by Ying Huang):
   potentially cleaner conceptually and seems to work without a
   userspace daemon, but apparently not documented anywhere
   except in the source files drivers/input/serio/serport.c
   and linux/drivers/input/mouse/sermouse.c

Now it's your turn to decide.

HTH
T.

--=20
Tilman Schmidt                          E-Mail: tilman@imap.cc
Bonn, Germany
Diese Nachricht besteht zu 100% aus wiederverwerteten Bits.
Unge=F6ffnet mindestens haltbar bis: (siehe R=FCckseite)


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