Subject: ttselect and minor dev bitflags.
To: None <current-users@sun-lamp.cs.berkeley.edu>
From: Niklas Hallqvist <niklas@appli.se>
List: current-users
Date: 04/25/1994 08:22:39
Is it desireable to have flags in the minor bits of tty
devices?  A common practice is to have dial-in/out lines
separated this way.  When dealing with such drivers a
problem pops up in ttselect() where the minor number
is used unmasked to get the tty struct.  E.g. the Amiga
serial driver has two meaningful minor numbers: 0 & 128.
When doing a select on the 128 device, a reference to
the 128th element of the d_ttys array is made, although
it's only 1 element long.  My feeling is that both these
nodes should use the same tty struct, so if we should
support such flags we have to provide a per-driver mask
ttselect can use to mask the minor dev# with.  What do
you think?

Niklas

Niklas Hallqvist	Phone: +46-(0)31-40 75 00
Applitron Datasystem	Fax:   +46-(0)31-83 39 50
Molndalsvagen 95	Email: niklas@appli.se
S-412 63  GOTEBORG, Sweden     mcsun!seunet!appli!niklas

------------------------------------------------------------------------------