On Tue, Jun 21, 2022 at 11:59:16PM +0900, Vincent MAILHOL wrote: > I (probably wrongly) assumed that urb::transfer_buffer_length was the > allocated length and urb::actual_length was what was actually being > transferred. Right now, I am just confused. Seems that I need to study > a bit more and understand the real purpose of > urb::transfer_buffer_length because I still fail to understand in > which situation this can be different from the allocated length. urb->transfer_buffer_length is the amount of data that the driver wants to send or expects to receive. urb->actual_length is the amount of data that was actually sent or actually received. Neither of these values has to be the same as the size of the buffer -- but they better not be bigger! Alan Stern
