Messages in this thread | | | From | (Alan Cox) | Subject | Re: TTY changes to 2.1.65 | Date | Tue, 25 Nov 1997 23:20:51 +0000 (GMT) |
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> Most of the time, people who are interested in using synchronous device > drivers are interested in using these devices for networking > applications --- i.e., X.25, Frame Relay, ISDN, etc. In those cases, > you usually want to interface the synchronous device directly into the > networking layer. There are in fact several synchoronous devices in the > kernel which are done in exactly this way, and so it doesn't touch the > tty code at all.
They often need too. The classic example is the Sparc, Mac, and PPC serial ports. These interfaces support synchronous mode on a byte level needing a very tty like interface
> line discipline could inform the low-level device driver what the > "framing character" is, and this information would be used to determine
No framing character. Think instead
ioctl(tty_fd, TIOCSSYNC, &sync_defs); v=TTY_LDISC_SYNCX25; ioctl(tty_fd, TIOCLDISC, &v); ioctl(tty_fd, SIOCGIFNAME, buf);
> stated above, synchronous devices will probably be always directly wired > into the networking stack.
Not the low speed stuff. The tty layer is exactly what they need. I think the framing is easy to handle too - just declare three of the error flags for frame end, abort, and checksum byte (for the hardware computed HDLC checksums off most chips).
Alan
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