(Query): [PATCH v4 2/4] usb gadget: Configure endpoint according to gadget speed.

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Hi Felipe/Alan

Any comments for the below query ?

On Thu, Jul 12, 2012 at 4:53 PM, Rajaram R <rajaram.officemail@xxxxxxxxx> wrote:
> Hi
>
>
> On Thu, Nov 18, 2010 at 6:17 PM, Tatyana Brokhman
> <tlinder@xxxxxxxxxxxxxx> wrote:
>>
>> Add config_ep_by_speed() to configure the endpoint according to the gadget
>> speed. Using this function will spare the FDs from handling the endpoint
>> chosen descriptor.
>>
>> Signed-off-by: Tatyana Brokhman <tlinder@xxxxxxxxxxxxxx>
>> ---
>>  drivers/usb/gadget/composite.c  |   76 +++++++++++++++++++++++++++++++++++++++
>>  drivers/usb/gadget/epautoconf.c |    1 +
>>  include/linux/usb/composite.h   |   21 +++++++++++
>>  include/linux/usb/gadget.h      |    3 ++
>>  4 files changed, 101 insertions(+), 0 deletions(-)
>>
> ---cut---
>
>> + */
>> +int config_ep_by_speed(struct usb_gadget *g,
>> +                       struct usb_function *f,
>> +                       struct usb_ep *_ep)
>> +{
>> +       struct usb_endpoint_descriptor *chosen_desc = NULL;
>> +       struct usb_descriptor_header **speed_desc = NULL;
>> +
>> +       struct usb_descriptor_header **d_spd; /* cursor for speed desc */
>> +
>> +       if (!g || !f || !_ep)
>> +               return -EIO;
>> +
>> +       /* select desired speed */
>> +       switch (g->speed) {
>> +       case USB_SPEED_HIGH:
>> +               if (gadget_is_dualspeed(g)) {
>> +                       speed_desc = f->hs_descriptors;
>> +                       break;
>> +               }
>> +               /* else: fall through */
>> +       default:
>> +               speed_desc = f->descriptors;
>> +       }
>> +       /* find descriptors */
>> +       for (d_spd = next_ep_desc(speed_desc); d_spd;
>> +             d_spd = next_ep_desc(d_spd+1)) {
>> +               chosen_desc = (struct usb_endpoint_descriptor *)*d_spd;
>> +               if (chosen_desc->bEndpointAddress == _ep->bEndpointAddress)
>> +                       goto ep_found;
>> +       }
>> +       return -EIO;
>> +
>> +ep_found:
>> +       /* commit results */
>> +       _ep->maxpacket = le16_to_cpu(chosen_desc->wMaxPacketSize);
>> +       _ep->desc = chosen_desc;

 Could you please comment on why do we need to update gadget's ep list
 with function's maxpacket ? Will this not affect when we switch
 functions ?
>
>> +
>> +       return 0;
>> +}
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