I'm not the world's top authority on the subject, but my understanding is that requests on endpoint 0 will either be standard device requests (such as reading basic information about the device), or device specific requests (things such as SET_IDLE for keyboard/mouse devices, which can be used to them to not to send any reports unless something has changed, or GET_MAX_LUN for usb bulk only transport storage devices).
CBWs and CSWs are part of the USB mass storage bulk only transport device spec, and are transferred on the bulk pipe (not endpoint 0), and are used to actually transfer data to and from the mass storage device, rather than to configure the device. Hope that helps (and is correct), Stuart -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Hou Xiang ZHU Sent: Wednesday, November 10, 2004 11:00 PM To: [EMAIL PROTECTED] Subject: [linux-usb-devel] URB,USB requests and CBW/CSW hello, A simple question related to linux usb concept here: I am reading the USB Spec2.0 , Mass Storage Spec. as well as linux usb code. I am little confused by some concept concerning URB,USB requests and CBW/CSW. In my understanding, each time host want to send request or data to usb device, it has to use usb_submit_urb(), The USB request has standard device request and Class-specific request, for standard request, it is used to get general USB device info. but when it is going to use class-specific request? what is the relationship between CBW/CSW and Class-specific request? so a URB contains either USB standard request or class-specific request or CBW? how about actual data(for example when writing a file to USB stick)? Thanks, Houxiang Zhu ------------------------------------------------------- This SF.Net email is sponsored by: Sybase ASE Linux Express Edition - download now for FREE LinuxWorld Reader's Choice Award Winner for best database on Linux. http://ads.osdn.com/?ad_idU88&alloc_id065&op=ick _______________________________________________ [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: Sybase ASE Linux Express Edition - download now for FREE LinuxWorld Reader's Choice Award Winner for best database on Linux. http://ads.osdn.com/?ad_idU88&alloc_id065&op=click _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
