Hello,
I've been investigating the USB Composite Gadget framework. I'm having
hard time with functions' setup function: in particular with queuing
requests on EP0. For instance, in f_acm.c we see at the end of
acm_setup() function[1] (debug stripped):
#v+
358 if (value >= 0) {
362 req->zero = 0;
363 req->length = value;
364 value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
368 }
371 return value;
#v-
However, in composite.c we can see[2]:
#v+
831 if (value >= 0) {
832 req->length = value;
833 req->zero = value < w_length;
834 value = usb_ep_queue(gadget->ep0, req, GFP_ATOMIC);
835 if (value < 0) {
837 req->status = 0;
838 composite_setup_complete(gadget->ep0, req);
839 }
840 }
#v-
So, does that mean that the request is queued two times? If so, is it an
error or should work fine?
The question arose while I was trying to port file_storage.c to a gadget
function so that it can be used in a multifunction gadget. I'm having
problem in coping with EP0 -- what should I do with queuing in file
storage to make the function work? I've created some code which compiles
and does not crash the kernel but it produces some warnings in a lower
lever (USB controller driver).
_______________________________________________________________
[1] http://lxr.linux.no/#linux+v2.6.30/drivers/usb/gadget/f_acm.c#L358
[2] http://lxr.linux.no/#linux+v2.6.30/drivers/usb/gadget/composite.c#L831
--
Best regards, _ _
.o. | Liege of Serenly Enlightened Majesty of o' \,=./ `o
..o | Computer Science, Michał "mina86" Nazarewicz (o o)
ooo +-<m.nazarewicz@xxxxxxxxxxx>-<mina86@xxxxxxxxxx>-ooO--(_)--Ooo--
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