On Fri, Oct 01, 2004 at 12:36:09PM +0100, Alan Cox wrote: > On Gwe, 2004-10-01 at 11:40, Al Borchers wrote: > > Unfortunately, many USB serial drivers' set_termios functions > > send an urb to change the termios settings and sleep waiting for > > it to complete. > > > > I just looked quickly, but it seems belkin_sa.c, digi_acceleport.c, > > ftdi_sio.c, io_ti.c, kl5usb105.c, mct_u232.c, pl2303.c, and whiteheat.c > > all sleep in their set_termios functions. > > > > If this locking in change_termios() stays, we are going to have to > > fix set_termios in all of these drivers. I am updating io_ti.c right > > now. > > How much of a problem is this, would it make more sense to make the > termios locking also include a semaphore to serialize driver side events > and not the spin lock ?
It would make the usb-serial drivers much simpler if this was turned into a semaphore. > We need some kind of locking there otherwise multiple parallel termios > setters resulting in truely strange occurences because driver authors > don't think about 64 parallel executions of ->change_termios() > > I can switch the lock around if you want. I'm all for it, if the tty core isn't messing with any line settings from interrupts. thanks, greg k-h ------------------------------------------------------- This SF.net email is sponsored by: IT Product Guide on ITManagersJournal Use IT products in your business? Tell us what you think of them. Give us Your Opinions, Get Free ThinkGeek Gift Certificates! Click to find out more http://productguide.itmanagersjournal.com/guidepromo.tmpl _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
