supporting more than ttyS*

Okash Khawaja okash.khawaja at
Wed Jun 7 09:40:12 EDT 2017

On Mon, Jun 05, 2017 at 06:11:13AM +0100, Okash Khawaja wrote:
> > On 4 Jun 2017, at 23:47, Gregory Nowak <greg at> wrote:
> > 
> >> On Sun, Jun 04, 2017 at 10:37:17AM +0200, Samuel Thibault wrote:
> >> Tom Fowle, on sam. 03 juin 2017 23:22:41 -0700, wrote:
> >>> Since many parallel ports are not bidirectional, it might be hard or
> >>> impossible to support indexing on a parallel port.
> >> 
> >> Yes.
> > 
> > That did occur to me as well. The blazer manual doesn't mention
> > anywhere that a ieee1284 cable is required. I have in fact used it
> > under a windows screen reader using a standard non-bidirectional cable
> > without issues. If a synthesizer supports indexing, would speakup
> > enable it when using a serial port, and disable it when using a
> > parallel port,
> Yes, that should be possible. Haven't looked at code but can't see why we can't disable it on parallel port.
> On a general note, I don't know much about parallel port programming yet, so there still might be issues unaddressed in the first pass. Of course we can come back to them in subsequent patches.

Indexing on /dev/lp* can be disabled by returning 0 from
synth_supports_indexing function in synth.c, whenever the device is lp*.
However, there are other places where input is also used. Ideally we
would disable all such functionality for lp*. Some synths also toggle
serial control lines which I am not sure will be possible or supported
by default in lp. Will have to look into this.

So I suggest, for the first pass we limit lp support to bns, acntsa,
dummy and txprt. Then we expand it to other synths based on their
functionality, e.g. on ltlk we disable indexing and interrogating to
print ROM version.

Let me know if that's okay.


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