Messages in this thread | | | Date | Sun, 6 Jul 2008 20:00:33 +0300 | From | Eduard - Gabriel Munteanu <> | Subject | Re: [PATCH] parport/ppdev: fix registration of sysctl entries |
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On Sun, 6 Jul 2008 17:08:02 +0100 Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
> > IMHO, there is one reason ppdev exists: allow both _safe_ and _raw_ > > access to the parallel port, and a much better alternative to the > > iopl stuff. > > And various devices support sharing protocols on the parallel port.
But isn't it incorrect to assume that sharing protocols allow multiple separate users? Why not have an userspace server mux/demux requests? Told more properly, such devices are multi-context, not multi-user.
AFAICT, this is similar to software mixing on soundcards, where we have an additional layer mixing (~ multiplexing) outgoing PCM streams.
The parallel port itself is not designed to be shared, so even if the device supports it, it does not mean we should allow independent access. We really should have an userspace lib/server to do this.
Eduard
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