On Tue, 2 Jul 2013, Victor Yeo wrote:
> Hi,
>
> > No, that's not right. Set-Config has only two stages, Setup and
> > Status; there is no Data stage. The flow is:
> >
> > Host Device
> > ----- Setup Packet ---> |
> > ----- Data0 Packet ---> |== Setup stage
> > <---- Ack Packet ------ |
> >
> > ----- In Packet ------> |
> > <---- Data1 Packet ---- |== Status stage
> > ----- Ack Packet -----> |
> >
> >
> >> "ACK the Status stage of an OUT control transfer", is it referring to
> >> the Third ACK packet? So UDC driver should ACK only after Data1 packet
> >> is sent via the usb_ep_queue()?
> >
> > I meant the Data1 packet above. The UDC driver should not send this
> > packet until the gadget driver tells it to (by calling usb_ep_queue).
> > Until then, it should send NAK in respond to the In packet.
>
> Is the Data1 packet above containing no data, such as this?
>
> PID !PID CRC
Yes.
> I do not see the gadget driver calling usb_ep_queue() for sending the
> Data1 packet. Please see the log below. Is there similar code in
> net2280.c handle_stat0_irqs() that handles Set-Config?
net2280.c does not handle Set-Config; it passes those requests to the
gadget driver.
> g_file_storage gadget: ep0-setup, length 8:
> 00000000: 00 09 00 00 00 00 00 00
> g_file_storage gadget: set configuration
> after kagen2_ep_queue
> kagen2_ep_queue 31 64 31
> [kagen2_ep_queue] 43425355 899e1008
> g_file_storage gadget: bulk-out, length 31:
> 00000000: 55 53 42 43 08 10 9e 89 00 00 00 00 00 00 0a 35
> 00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> g_file_storage gadget: SCSI command: SYNCHRONIZE CACHE; Dc=10, Dn=0;
> Hc=10, Hn=0
> g_file_storage gadget: ep0-setup, length 8:
> 00000000: 80 08 00 00 00 00 01 00
> g_file_storage gadget: get configuration
> ept0 in queue len 0x1, buffer 0xc1289800
> ep0_complete
> g_file_storage gadget: ep0-in, length 1:
> 00000000: 01
> attention condition
I can't tell what's going on in your log. Look at the
FSG_STATE_CONFIG_CHANGE case in handle_exception(). Here's the code:
rc = do_set_config(fsg, new_config);
if (fsg->ep0_req_tag != exception_req_tag)
break;
if (rc != 0) // STALL on errors
fsg_set_halt(fsg, fsg->ep0);
else // Complete the status stage
ep0_queue(fsg);
break;
It calls do_set_config(). After that, fsg->ep0_req_tag should be equal
to exception_req_tag and rc should be equal to 0. Therefore the code
will call ep0_queue(), which calls usb_ep_queue().
You can add some debugging printk statements to make sure it really
does behave this way.
Alan Stern
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