Re: [OT] RE: UDI and Free Software

david parsons (o.r.c@p.e.l.l.p.o.r.t.l.a.n.d.o.r.u.s)
7 Oct 1998 13:37:06 -0700

In article <linux.kernel.m0zQyUP-000aNTC@the-village.bc.nu>,
Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
>> it lacks stuff like check_region that is central to the Linux philosophy.
>> UDI on Linux would also be useless for parallel scanners - UDI can't
>> describe talking to the parport management layer
>>
>> Exactly. So you'd have to do an extra memory copy in the Linux<->UDI
>> interface layer. It'll be slow, but you an make it work. See my
>> previous comments about UDI always being a poor second cousin to real
>> native drivers.....
>
>It isnt a case of extra copies. Its fundamentally impossible for a UDI
>driver to access the parallel port under Linux because there is no UDI speak
>for 'parport_*' calls which you _have_ to make. There are numerous other
>examples like that.

There are a few solutions to that.

First, if needed, the UDI people should modify their spec to accomodate
the existing Linux device driver.

Secondly, vendors will just write a UDI parallel port driver and tell
customers that if they want to use this driver in Linux, they need to
disable the existing lp driver and use the UDI one instead [1].

Thirdly, vendors will continue to say "sorry, we don't support Linux"

____
david parsons \bi/ [1: yup, and the UDI people would have to write UDI
\/ drivers for all the things that depend on the
existing driver. This would be good, because
it would give a stack to stack comparison of UDI
vs the native interface for that particular kernel
version.]

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