Thanks Samuel. That email thread is helpful too. Appreciate your patience. > On 15 Nov 2016, at 18:47, Samuel Thibault <samuel.thibault@xxxxxxxxxxxx> wrote: > > Okash Khawaja, on Tue 15 Nov 2016 06:58:24 +0000, wrote: >> On Tue, Nov 15, 2016 at 6:36 AM, Samuel Thibault <[2] >> samuel.thibault@xxxxxxxxxxxx> wrote: >>> And how will /dev/ttyx be used? >> >> It won't be used. As a line discipline speakup will plug higher in the >> stack. >> >> Could you explain this more? May be a concrete example? >> I mean is this something that a user space application will read from? > > Normally what happens, for instance when running a serial mouse driver, > is that a userland program opens /dev/ttyS0, calls an ioctl to set the > N_MOUSE line discipline, and then leaves /dev/ttyS0 alone. All the work > is done by the line discipline, userland doesn't do any read/write on > the device. I.e. the line discipline catches the data before it reaches > userland. > >> If so, what is the specific advantage of speakup being line >> discipline? > > It's simply because that's the way things work for all other drivers > "over serial lines", like mice, joysticks ppp, gsm, etc. There is then > no risk for speakup to break at all, these have been working for decades > without a fuss. And they will work with anything that looks more or less > like a serial port, be it ISA, PCI, USB, bluetooth, irda, whatever. > >> Please add any links/documentation that will help >> understand this. Thanks > > Unfortunately line disciplines are a rather obscure area not many people > work on. > > There is linux/Documentation/serial/tty.txt > >>> Also is there a link to where you pasted your idea from? >> >> I wrote it. >> >> Of course. I mean a link to full discussion to get more context. > > There is a thread starting here: > > http://www.spinics.net/lists/linux-serial/msg21752.html > > Samuel _______________________________________________ Speakup mailing list Speakup@xxxxxxxxxxxxxxxxx http://linux-speakup.org/cgi-bin/mailman/listinfo/speakup
