On Fri, Apr 23, 2004 at 04:30:08PM -0700, Pete Zaitcev wrote:
> On Sat, 24 Apr 2004 01:07:19 +0200 (CEST) Jan Capek <[EMAIL PROTECTED]> wrote:
> > static void ftdi_set_termios (struct usb_serial_port *port, struct termios
> > *old_termios)
> > { /* ftdi_termios */
>
> > - /* FIXME -For this cut I don't care if the line is really changing or
> > - not - so just do the change regardless - should be able to
> > - compare old_termios and tty->termios */
> > + /* Check if any change in termios settings occured*/
> > + if (old_termios) {
> > + if ((cflag == old_termios->c_cflag) &&
> > + (RELEVANT_IFLAG(port->tty->termios->c_iflag) ==
> > + RELEVANT_IFLAG(old_termios->c_iflag))) {
> > + dbg("%s - nothing to change", __FUNCTION__);
> > + return;
> > + }
> > + old_baudrate = old_termios->c_cflag & CBAUD;
> > + }
>
> This is a suspect, because I hit an issue with such optimization
> in mct_u232 just recently. There was a certain path which fools
> the comparison _and_ the 2.4 and 2.6 do it differently (one starts
> card from an open and another doesn't). I'd need to have a closer
> look, because I do not remember details now.
>
> In general though, do not do such acrobatics in component drivers.
> Greg, do you agree?
Hm, if you do want to check stuff like that, make sure your logic is
correct :)
But yes, it's probably just best to set the line setting again, and not
worry about old_termios most of the time. That reduces complexity and
potential bugs.
thanks,
greg k-h
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