On Wed, Jun 25, 2003 at 02:58:28PM -0400, Louis A. Mamakos wrote: > I think the problem is that the USB hardware doesn't try to read data > from the peripheral until the user-mode code does a read(2) system > call. I had this problem with the ugen device. I would guess that > the ucom/umodem devices could use the tty clist infrastructure as > the intermediate buffer for data to be stuck into absent the user > application doing a read.
ugen can't preread from the device because it has to be generic. And without the appilication to call read(2) it has absolutely no clue about the number of bytes that can be read without harming the device. There are many devices out there where the number of bytes that you request do matter. ucom is different - it has a device specific driver that knows the hardware and starts receiving bytes from the hardware once the application opens the device. -- B.Walter BWCT http://www.bwct.de [EMAIL PROTECTED] [EMAIL PROTECTED] _______________________________________________ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[EMAIL PROTECTED]"
