Date: Sun, 20 Jun 2004 10:50:00 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: phk@phk.freebsd.dk Cc: arch@freebsd.org Subject: Re: [REVIEW] move tty lock/initial up in the stack Message-ID: <20040620.105000.106880101.imp@bsdimp.com> In-Reply-To: <82937.1087721102@critter.freebsd.dk> References: <20040619.145736.91276883.imp@bsdimp.com> <82937.1087721102@critter.freebsd.dk>
next in thread | previous in thread | raw e-mail | index | archive | help
In message: <82937.1087721102@critter.freebsd.dk> "Poul-Henning Kamp" <phk@phk.freebsd.dk> writes: : In an ideal world the hardware driver would be reduced to just that, : a few simple primitives, "start", "config", "open", "close" and a : backcall "rint" with received data and modem status changes. This : is not too unlike what Marcel have done with uart(4) I guess I'm curious how the tty/cua split would be done in this scheme. Of course I'm reimplementing the Cyclades Z driver to try to use uart, which is why I'm getting curious. I don't know if this will wind up working or not, but since 95% of the hardware interface is two circular buffers in memory, which does seem to map mostly onto Marcel's model. Time will tell... I also have porting the stallion driver to current. I can do this by a simple hack on the old driver, or a rewrite. I'll use my Z experience to decide. : The major difference is that serial ports are rapidly headed into : the sunset whereas disks are very much a hot topic. I suspect that the decline will last for a long time. Many of the usb devices that I've seen are really usb to rs232 to thing, so I suspect that it is a case of 'Serial ports are dead, long live the serial ports' : The pty driver is the only really interesting tty driver these days : as most terminal access is through sshd, telnetd or xterm. There's still a lot of people using ppp for dialup connections, even in the day of broadband. I suspect that will be the other large area of heavy use. : Currently I see two ways to get ptys out form under giant: : : 1) write an entirely new pty driver which is totally separate : from the rest of the tty code (We don't need slip/ppp/netgraph : support on ptys anyway). : : 2) clean up the tty code enough that the pty can be deGiantized, : paving the road for the rest of the tty drivers to get the : same treatment, should somebody else care enough. Are you looking for help on the latter? : I havn't quite made up my mind yet, and have resorted to some general : polishing while I try to make sense of this stuff. To some extent I : already regret getting my fingers dirty over here. OK. Warner
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20040620.105000.106880101.imp>