On Tue, May 06 2014, Andrzej Pietrasiewicz wrote:
> Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxx>
Acked-by: Michal Nazarewicz <mina86@xxxxxxxxxx>
> diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
> index 4e8aaa6..47a6f4e 100644
> --- a/drivers/usb/gadget/composite.c
> +++ b/drivers/usb/gadget/composite.c
> @@ -454,8 +456,46 @@ static int config_desc(struct usb_composite_dev *cdev, unsigned w_value)
>
> }
>
> - /* This is a lookup by config *INDEX* */
> w_value &= 0xff;
> + /*
> + * This is a lookup to make non-compliant USB hosts happy.
> + *
> + * By non-compliant USB hosts I mean those which only ask for
> + * configuration @index 0.
> + * If one configuration is marked "special" by storing
> + * its address in cdev->os_desc_config, we try returning
> + * exactly this configuration.
> + *
> + * Otherwise, regular list lookup is performed.
> + *
> + * If we are connected to a compliant USB host _and_
> + * one configuration is "special" we report it @ index 0,
> + * but report remaining configurations as well - with adjusted
> + * indices.
> + */
> + c = cdev->os_desc_config;
> + if (c) {
> + if (!w_value) {
> + switch (speed) {
> + case USB_SPEED_SUPER:
> + if (!c->superspeed)
> + goto list_lookup;
> + break;
> + case USB_SPEED_HIGH:
> + if (!c->highspeed)
> + goto list_lookup;
> + break;
> + default:
> + if (!c->fullspeed)
> + goto list_lookup;
> + }
> +
> + return config_buf(c, speed, cdev->req->buf, type);
> + }
> + --w_value; /* account for conf returned @ index 0 */
> + }
This is non-ideal since the body of the if is repeated twice. Perhaps
it could be folded into the loop, something like:
/* This is a lookup by config *INDEX* */
w_value &= 0xff;
struct list_head *pos = &cdev->configs;
c = cdev->os_desc_config;
if (c)
goto check_config;
while ((pos = pos->next) != &cdev->configs) {
c = list_entry(pos, typeof(*c), list);
/* skip OS config which is handled separately */
if (c == cdev->os_desc_config)
continue;
check_config:
/* ignore configs that won't work at this speed */
switch (speed) {
case USB_SPEED_SUPER:
if (!c->superspeed)
continue;
break;
case USB_SPEED_HIGH:
if (!c->highspeed)
continue;
break;
default:
if (!c->fullspeed)
continue;
}
if (w_value == 0)
return config_buf(c, speed, cdev->req->buf, type);
w_value--;
}
Not tested.
> +list_lookup:
> + /* This is a lookup by config *INDEX* */
> list_for_each_entry(c, &cdev->configs, list) {
> /* ignore configs that won't work at this speed */
> switch (speed) {
--
Best regards, _ _
.o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o
..o | Computer Science, Michał “mina86” Nazarewicz (o o)
ooo +--<mpn@xxxxxxxxxx>--<xmpp:mina86@xxxxxxxxxx>--ooO--(_)--Ooo--
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