On Tue, 21 Aug 2012, Kevin Cernekee wrote: > On Tue, Aug 21, 2012 at 11:08 AM, Felipe Balbi <balbi@xxxxxx> wrote: > > Then stick to a workqueue... but could you let me know why exactly you > > have to fake SET_CONFIGURATION/SET_INTERFACE requests ? Is this a > > silicon bug or a silicon feature ? That's quite weird to me. > > It is a silicon feature: the core will intercept SET_CONFIGURATION / > SET_INTERFACE requests, store wValue/wIndex in the appropriate > USBD_STATUS_REG field (cfg/intf/altintf), send an acknowledgement to > the host, and raise a control interrupt. Your explanation is not clear. The operations you listed are exactly what any UDC should do when it receives any control request: It should store the bRequestType, bRequest, wValue, wIndex, and wLength values in appropriate registers, send an ACK back to the host, and generate an IRQ. What's special about Set-Config and Set-Interface? The only thing to watch out for is the status stage of the control transfer. The hardware must not complete the status stage for you; that would be a violation of the USB-2 spec. (The only exception is for Set-Address requests.) > I haven't found it to be terribly helpful, but I don't know of a way > to turn it off. Why would you want to turn this off? Isn't is exactly what you want to have happen? And why do you need a workqueue to handle the request? Alan Stern
