On Mon, Apr 19, 2004 at 03:41:41PM -0600, [EMAIL PROTECTED] wrote: > I have been playing with a USB->tty interface device > (this is a USB 1.1 product from Sewell, based on the pl-2303, although > I dont think that the exact product is relevant). > > I am using the USB implementation in Fedora2t1, kernel 2.6.1-1.65 . > > I am sending some short (4char) signals to a X10 driver, an ON signal > and after a delay, an OFF signal. > > Now EVERYTHING works as expected when I use a REAL serial port (ttyS1). > > With the USB->tty port the OFF signal never gets sent, rather > the RTS drops as the program exits BEFORE the characters are sent to > the device. If I put in either a second write -or- a 5 second sleep > at the end of the program, then the 4char write at the end of the > program succeeds (as seen by watching a breakout box). > > So, are there known timing problems with the USB->Serial driver?
Depends on the driver, some work properly, others work a bit looser, as you've seen :) The pl2303 driver will not wait to drain all pending databits before dropping the signal as you have seen. Some kind of patch like Pete has in 2.4 would need to be added to change this. Sorry, greg k-h ------------------------------------------------------- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
