Date: Mon, 8 Dec 2008 13:31:06 +0000
From: Jamie Lokier <jamie@shareable.org>
To: Laurent Pinchart <laurentp@cse-semaphore.com>
Cc: linux-mtd@lists.infradead.org, dedekind@infradead.org,
       v4l-dvb-maintainer@linuxtv.org, LKML <linux-kernel@vger.kernel.org>,
       arnd@arndb.de
Subject: Re: UBI/DVB ioctl conflict?
Message-ID: <20081208133106.GA16354@shareable.org>
References: <20081207095811.13b51cca@zod.rchland.ibm.com> <1228717226.13686.89.camel@sauron> <200812081041.14178.laurentp@cse-semaphore.com>
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Laurent Pinchart wrote:
> Correct me if I'm wrong, but doesn't this only matters for devices
> that would implement both the UBI and DVB API on the same inode ?
> That would be quite unlikely.

Overlapping ioctls prevent strace(1) from showing ioctls properly.

For example, here's something you see often in strace of programs
using stdio, when it calls isatty():

ioctl(1, SNDCTL_TMR_TIMEBASE or TCGETS, 0xbfaaa864) = -1 ENOTTY (Inappropriate ioctl for device)

Or if it is a terminal:

ioctl(1, SNDCTL_TMR_TIMEBASE or TCGETS, {c_iflags=0x6d02, c_oflags=0x5, c_cflags=0x4bf, c_lflags=0x8a3b, c_line=0, c_cc="\x03\x1c\x7f\x15\x04\x00\x01\xff\x11\x13\x1a\xff\x12\x0f\x17\x16\xff\x00\x00"}) = 0

-- Jamie
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