MPSAFE TTY schedule [uart vs sio]

Takahashi Yoshihiro nyan at
Sat Jul 5 12:25:42 UTC 2008

In article <29489C48-93A2-41D9-9EF1-5395A673A9B3 at>
Marcel Moolenaar <xcllnt at> writes:

> > The uart probably works for some 16550 based devices but does not work
> > for other one like multi-port devices.
> The design principle of uart(4) is that it does not know
> about multi-port hardware. It controls a single serial
> port only. For multi-port hardware you must have multiple
> nodes on a bus or use an umbrella driver, such as puc(4),
> quicc(4) or scc(4). Those drivers provide attachments for
> every port.
> I suspect that support for multi-port devices is not to
> hard to do on pc98...

Many serial devices on pc98 use indirect I/O space, so resource
management is quite complex.  Therefore, it may need more work you

At the starting point, I have added CBus frontend and fixed console
support for pc98.

TAKAHASHI Yoshihiro <nyan at>

More information about the freebsd-arch mailing list