Hi,
Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> writes:
> On Tue, 26 Sep 2017, Felipe Balbi wrote:
>
>> > Does uvc use isochronous transfers? I assume it would, since it's a
>> > video protocol.
>>
>> yes, it does :-)
>>
>> > dummy-hcd does not support isochronous. I don't know what would happen
>>
>> really? Then why is it registering iso endpoints to the gadget layer?
>>
>> static const struct {
>> const char *name;
>> const struct usb_ep_caps caps;
>> } ep_info[] = {
>> #define EP_INFO(_name, _caps) \
>> { \
>> .name = _name, \
>> .caps = _caps, \
>> }
>>
>> /* everyone has ep0 */
>> EP_INFO(ep0name,
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_CONTROL, USB_EP_CAPS_DIR_ALL)),
>> /* act like a pxa250: fifteen fixed function endpoints */
>> EP_INFO("ep1in-bulk",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_BULK, USB_EP_CAPS_DIR_IN)),
>> EP_INFO("ep2out-bulk",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_BULK, USB_EP_CAPS_DIR_OUT)),
>> EP_INFO("ep3in-iso",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_ISO, USB_EP_CAPS_DIR_IN)),
>> EP_INFO("ep4out-iso",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_ISO, USB_EP_CAPS_DIR_OUT)),
>> EP_INFO("ep5in-int",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_INT, USB_EP_CAPS_DIR_IN)),
>> EP_INFO("ep6in-bulk",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_BULK, USB_EP_CAPS_DIR_IN)),
>> EP_INFO("ep7out-bulk",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_BULK, USB_EP_CAPS_DIR_OUT)),
>> EP_INFO("ep8in-iso",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_ISO, USB_EP_CAPS_DIR_IN)),
>> EP_INFO("ep9out-iso",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_ISO, USB_EP_CAPS_DIR_OUT)),
>> EP_INFO("ep10in-int",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_INT, USB_EP_CAPS_DIR_IN)),
>> EP_INFO("ep11in-bulk",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_BULK, USB_EP_CAPS_DIR_IN)),
>> EP_INFO("ep12out-bulk",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_BULK, USB_EP_CAPS_DIR_OUT)),
>> EP_INFO("ep13in-iso",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_ISO, USB_EP_CAPS_DIR_IN)),
>> EP_INFO("ep14out-iso",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_ISO, USB_EP_CAPS_DIR_OUT)),
>> EP_INFO("ep15in-int",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_INT, USB_EP_CAPS_DIR_IN)),
>> /* or like sa1100: two fixed function endpoints */
>> EP_INFO("ep1out-bulk",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_BULK, USB_EP_CAPS_DIR_OUT)),
>> EP_INFO("ep2in-bulk",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_BULK, USB_EP_CAPS_DIR_IN)),
>> /* and now some generic EPs so we have enough in multi config */
>> EP_INFO("ep3out",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_ALL, USB_EP_CAPS_DIR_OUT)),
>> EP_INFO("ep4in",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_ALL, USB_EP_CAPS_DIR_IN)),
>> EP_INFO("ep5out",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_ALL, USB_EP_CAPS_DIR_OUT)),
>> EP_INFO("ep6out",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_ALL, USB_EP_CAPS_DIR_OUT)),
>> EP_INFO("ep7in",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_ALL, USB_EP_CAPS_DIR_IN)),
>> EP_INFO("ep8out",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_ALL, USB_EP_CAPS_DIR_OUT)),
>> EP_INFO("ep9in",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_ALL, USB_EP_CAPS_DIR_IN)),
>> EP_INFO("ep10out",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_ALL, USB_EP_CAPS_DIR_OUT)),
>> EP_INFO("ep11out",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_ALL, USB_EP_CAPS_DIR_OUT)),
>> EP_INFO("ep12in",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_ALL, USB_EP_CAPS_DIR_IN)),
>> EP_INFO("ep13out",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_ALL, USB_EP_CAPS_DIR_OUT)),
>> EP_INFO("ep14in",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_ALL, USB_EP_CAPS_DIR_IN)),
>> EP_INFO("ep15out",
>> USB_EP_CAPS(USB_EP_CAPS_TYPE_ALL, USB_EP_CAPS_DIR_OUT)),
>>
>> #undef EP_INFO
>> };
>>
>> > if you tried it, but one way or another it would not work the way you
>> > want.
>>
>> if that's really the case, then maybe we should remove all the iso
>> endpoints from dummy. Right?
>
> Or comment them out, in case somebody decides to add isochronous
Kinda pointless to leave commented out code, but fine.
> support in the future. Yes, there's no point having them in the
> driver, given the way it works currently. All isochronous URBs
> complete with a -ENOSYS error status:
>
> switch (usb_pipetype(urb->pipe)) {
> case PIPE_ISOCHRONOUS:
> /* FIXME is it urb->interval since the last xfer?
> * use urb->iso_frame_desc[i].
> * complete whether or not ep has requests queued.
> * report random errors, to debug drivers.
> */
> limit = max(limit, periodic_bytes(dum, ep));
> status = -ENOSYS;
> break;
>
> The comment could be improved too. I'll send in a patch.
Thank you :-)
--
balbi
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