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Date: Fri, 12 Jun 2015 15:26:26 -0700
From: Greg KH <gregkh@linuxfoundation.org>
To: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: julien.dehee@gmail.com, abbotti@mev.co.uk, hsweeten@visionengravers.com,
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Subject: Re: [PATCH] staging: comedi: replace ENOSYS by proper error codes
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On Fri, Jun 12, 2015 at 10:06:16PM +0100, One Thousand Gnomes wrote:
> On Fri, 12 Jun 2015 13:43:27 -0700
> Greg KH <gregkh@linuxfoundation.org> wrote:
> 
> > On Fri, Jun 12, 2015 at 10:20:38PM +0200, julien.dehee@gmail.com wrote:
> > > From: Julien Dehee <julien.dehee@gmail.com>
> > > 
> > > comedi/comedi_fops.c
> > >     use ENODEV following open manual
> 
> That should probably be ENXIO by a strict reading, but Linux has always
> used ENODEV 8)
> 
> > > 
> > > comedi/drivers.c
> > >     use ENOTTY following ioctl manual
> > > 
> > > drivers/serial2002.c
> > >     use ENOTTY following ioctl manual
> > 
> > What do you mean by "ioctl manual"?
> 
> man 2 ioctl
> 
> Unknown ioctls on a device should error with ENOTTY. It's one of
> those crazy pieces of Unix history.

Note that the man 2 ioctl interface is not always what the kernel
exposes, but rather, what your libc exposes to other programs.  So
setting these kernel values might not change what you get all the way
through, have you tested it?

thanks,

greg k-h