devnum 1 is assigned to the root hub, and Devnum 2 is assigned to the first device connected to the root hub. Any subsequence device attached to the root hub via USB hub will increment the devnum by 1. In your case, I believe the PL2303 device would be the first device connected to the root hub, hence it is assigned with address 2.
Also, In each USB frame, there can be multiple "active" URB as long as they don't go to the same pipe (ie same USB address and endpoint) In your case, you can have Interrupt URB, Control URB, and Bulk URB all on the same USB frame. Pei -----Original Message----- From: thomas chen <[EMAIL PROTECTED]> To: David Brownell <[EMAIL PROTECTED]> Cc: Greg KH <[EMAIL PROTECTED]>; [EMAIL PROTECTED] <[EMAIL PROTECTED]> Date: Thursday, January 16, 2003 7:49 PM Subject: Re: [linux-usb-devel] NACK from device > >thanks for the pointers.... it turned out that it is being queued >but for the wrong reason... > >in the submit_urb.. (this is the SL811)... it checks the >RH.DEVNUM (which is 1)... against the PIPEDEVICE which is 2... >so it does not send it out and queue it up... and i am now trying >to find out where the 2 comes from???? (all the communication >were working ... ie pipedevice(pipe) == 1 until /dev/ttyUSB0 is >opened and i guess pl2302 is involved... > >like an onion... just keep peeling!!! > >David Brownell wrote: >> >> thomas chen wrote: >> > ohci can handle two urb_submit by DELAYing one for the next frame? >> >> No, it handles them by _queueing_ the second one so that it'll >> start after the first one finishes. In the case of OHCI, the >> typical case is that the hardware automatically advances that >> queue ... no software attention is needed until later, unless >> there's some kind of fault seen with the first URB. (And NAK >> isn't a fault.) >> >> > i guess the question is that can two packets be sent in the same frame? >> >> URB != packet. At USB 1.1 speeds, multiple packets per frame >> will be typical. >> >> - Dave >> >> > if not.. then the driver is responsible for delaying one??? i guess that >> > is the problem... the driver i have does not seem to do that properly >> > and slave starts sending nack after that... >> > >> > thanks >> > > > >------------------------------------------------------- >This SF.NET email is sponsored by: Thawte.com >Understand how to protect your customers personal information by implementing >SSL on your Apache Web Server. Click here to get our FREE Thawte Apache >Guide: http://ads.sourceforge.net/cgi-bin/redirect.pl?thaw0029en >_______________________________________________ >[EMAIL PROTECTED] >To unsubscribe, use the last form field at: >https://lists.sourceforge.net/lists/listinfo/linux-usb-devel ------------------------------------------------------- This SF.NET email is sponsored by: Thawte.com - A 128-bit supercerts will allow you to extend the highest allowed 128 bit encryption to all your clients even if they use browsers that are limited to 40 bit encryption. Get a guide here:http://ads.sourceforge.net/cgi-bin/redirect.pl?thaw0030en _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
