Date: Sat, 28 Jun 2003 14:03:16 +0200 From: Bernd Walter <ticso@cicely12.cicely.de> To: Danny Braniss <danny@cs.huji.ac.il> Cc: freebsd-hackers@freebsd.org Subject: Re: USB, select/poll for ucom Message-ID: <20030628120315.GZ68295@cicely12.cicely.de> In-Reply-To: <E19WC8s-0006B0-00@cs.huji.ac.il> References: <E19WC8s-0006B0-00@cs.huji.ac.il>
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On Sat, Jun 28, 2003 at 12:37:10PM +0300, Danny Braniss wrote: > [...] > > have fun. the mindshare book is good. however, it took me a long > > time to get a usb 'aha' moment and understand its twisty maze was > > really a workable design obscured by standardese... I suspect it is a > > problem in the usb chipset driver for the com part. ttypoll just says > > 'you have data in the buffer' so for some reason the data isn't making > > into the tty buffer. > > > > Warner > > Im amazed at how some of you can write a driver based on the Spec. Docs! > > here is a pearl i came across reading the USB spec for 1.1, page 43 > > 'The maximum allowable interrupt data payload > size is 64 bytes or less for full-speed.' The device will tell you his personal limits for the given endpoint. See wMaxPacketSize in usb_endpoint_descriptor_t. The specs only tell you that a device can't tell >64 byte as the maximum for an interrupt endpoint. -- B.Walter BWCT http://www.bwct.de ticso@bwct.de info@bwct.de
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