On Wed, 4 Apr 2007, Wael Adel wrote: > On 4/4/07, Alan Stern <[EMAIL PROTECTED]> wrote: > > On Wed, 4 Apr 2007, nesta wrote: > > > > > hi all, > > > i want to know what is the max usb packet size that i can send over an usb > > > cable connected between a computer Host and the omap kit. > > > > > > note that this kit is full speed device not support a high speed ? > > > could it be 256 Bytes for example?or what? > > > > 64 bytes for Bulk, Control, and Interrupt. 1023 bytes for Isochronous > > (unless the OMAP has its own restrictions). > > are all of these numbers in bytes?
Yes. Read what I wrote. > if so, assume that i m using bulk endpoint and i have a file of size of 5*64 B > > what is faster is to write data in 5 times each of 64 B size or > is to write data in 1 time of 5*64 B? It's faster to write 5*64 bytes in one request. > please tell me why any choice would be faster if u know? The amount of time required on the bus will be the same either way. But this way you have to make only one call to usb_submit_urb() instead of five calls, so you save CPU time. > also i m very surprised that the max usb packet size of my host computer is 2? > does not this seem to me too slow?i mean how it can support fast data > transfer? It sounds completely wrong. What do you see in /proc/bus/usb/devices? (You may have to do "mount -t usbfs none /proc/bus/usb" before you can access that file.) Alan Stern ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
