Hello, Any news on this? Samuel Thibault, on Sun 06 Mar 2016 18:45:57 +0100, wrote: > Greg, on Sat 05 Mar 2016 11:14:59 -0800, wrote: > > There is a way to talk to any serial port from within the kernel, I > > thought the serio layer did it, or maybe it was bluetooth, but I can't > > find it at the moment, sorry. Try digging around a bit, it's there > > somewhere... > > I guess you mean linux/drivers/input/serio/serport.c? > > It is apparently using a tty line discipline (N_MOUSE), yes. That was > one of the ways we were considering for speakup indeed. > > The question is: how does speakup set the line discipline from kernel > land? One of the goals of speakup is to be available before userland > works (otherwise we could as well just move the drivers to userland), so > we don't have any userland helper to set the line disciline up. > > And even before setting up the line discipline, how can speakup open > the port? We don't have a process context or /dev/, so we can't just > use sys_open and alike. What we could use is some function which takes > a minor/major pair or a device name, and returns a filp, then we can > tty_set_ldisc(N_SPEAKUP) on file_tty(filp), but I don't know if such > thing exists? That would probably be building a struct inode (getting > inspired from fs/ramfs/), then just open it? Something like: > > struct inode *inode = new_inode(sb); > > init_special_inode(inode, S_IFCHR, MKDEV(major, minor)); > filp = get_empty_filp(); > do_dentry_open(filp, inode, NULL, NULL); > struct tty_struct *tty = file_tty(filp); > tty_set_ldisc(tty, N_SPEAKUP); > > Samuel -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
