Re: no ioctls for serial ports? [was Re: LANANA: To Pending DeviceNum

Jakob Østergaard
2001-05-20T15:27:22Z

On Sun, May 20, 2001 at 10:45:07AM -0400, Alexander Viro wrote:
>
>
> On Sun, 20 May 2001, Abramo Bagnara wrote:
>
> > > It may have several. Which one?
> >
> > Can you explain better this?
>
> Example: console. You want to be able to pass font changes. I'm
> less than sure that putting them on the same channel as, e.g.,
> keyboard mapping changes is a good idea. We can do it, but I don't
> see why it's natural thing to do. Moreover, you already have
> /dev/vcs<n> and /dev/vcsa<n>. Can you explain what's the difference
> between them (per-VC channels) and keyboard mapping (also per-VC)?
>
> Face it, we _already_ have more than one side band.

Wouldn't it be natural to
write(fd, <control type>)
write(fd, <control information)
read(fd, reply)

Only one control file for all controls a device understands

>
> Moreover, we have channels that are not tied to a particular device -
> they are for a group of them. Example: setting timings for IDE controller.
> Sure, we can just say "open /dev/hda instead of /dev/hda5", but then we
> are back to the "find related file" problem you tried to avoid.

If the IDE controller is a device we can control, it should have a device
file and a control device file.

Problem solved, AFAICS.

Controlling an IDE controller by writing to a device that's hanging on one
of it's busses is a hack, IMO.

--
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