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SubjectRe: [PATCH v4 1/4] usb gadget: Add usb_endpoint_descriptor to be part of the struct usb_ep
On Thu, Nov 18, 2010 at 02:46:38PM +0200, Tatyana Brokhman wrote:
> Change usb_ep_enable() prototype to use endpoint descriptor from usb_ep.
> This optimization spares the FDs from saving the endpoint chosen
> descriptor.

Why is this a good thing to do?

> This optimization is not full though. To fully exploit this
> change one needs to update all the UDCs as well since in the current
> implementation each of them saves the endpoint descriptor in it's
> internal (and extended) endpoint structure.

Do you do that optimization later on in this patch series?

> diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
> index 006412c..937c8fa 100644
> --- a/include/linux/usb/gadget.h
> +++ b/include/linux/usb/gadget.h
> @@ -131,20 +131,22 @@ struct usb_ep_ops {
> * @maxpacket:The maximum packet size used on this endpoint. The initial
> * value can sometimes be reduced (hardware allowing), according to
> * the endpoint descriptor used to configure the endpoint.
> - * @driver_data:for use by the gadget driver. all other fields are
> - * read-only to gadget drivers.
> + * @driver_data:for use by the gadget driver.

Why did you change the "all other fields..." portion?

> + * @desc: endpoint descriptor. This pointer is set before the endpoint is
> + * enabled and remains valid until the endpoint is disabled.
> *
> * the bus controller driver lists all the general purpose endpoints in
> * gadget->ep_list. the control endpoint (gadget->ep0) is not in that list,
> * and is accessed only in response to a driver setup() callback.
> */
> struct usb_ep {
> - void *driver_data;
> + void *driver_data;
>
> - const char *name;
> - const struct usb_ep_ops *ops;
> - struct list_head ep_list;
> - unsigned maxpacket:16;
> + const char *name;
> + const struct usb_ep_ops *ops;
> + struct list_head ep_list;
> + unsigned maxpacket:16;
> + const struct usb_endpoint_descriptor *desc;

Please don't reformat, it's hard to see what really was changed here.

thanks,

greg k-h


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