Re: devfs + PCI serial card = no extra serial ports

Bryan Whitehead
2003-03-10T18:15:20Z

[snip]
> There is nothing in devfs that prevents you from registering
> devfs devices even if they are not yet bound to specific hardware
> (you do not need a sysfs mapping, for example). So, you should be
> able to register /dev/tts/0..N at initialization, where N is the
> maximum number of serial devices you want to support.

are you saying there is a way to force devfs to make more entries in
/dev/tts/ without any hardware being attached to the entries? Then i can
use setserial? so on boot I'd have 4 entries in /dev/tts ?

Or are you saying I write a script to goto /dev/tts after boot and mknod
the ports that are missing?

> Another approach, which I think provides a little more
> information to users, makes for a more readable /dev tree and should
> make some programs a few cycles faster would be to what my version of
> /dev/loop does (not the one currently in Linus's tree, alas): start by
> just creating /dev/tts/0, and then create /dev/tts/n+1 whenever
> /dev/tts/n is assigned and /dev/tts/n+1 has not already been defined.
> For /dev/loop, it was also useful to have the extra devices unregister
> when the highest number device became undefined (if a device in the
> middle were de-defined, it would not disappear until all higher
> numbered devices were also de-defined).
>
> Is this the issue, or do I misunderstand?
>
> Adam J. Richter __ ______________ 575 Oroville Road
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--
Bryan Whitehead
SysAdmin - JPL - Interferometry Systems and Technology
Phone: 818 354 2903
driver@jpl.nasa.gov