Hi Felipe,
Can we get this patch into 4.19-rc6? The patch is simple and well
understood and solves a real problem -- functionfs control requests
will not work without it.
Thanks,
Jerry
On Mon, Jul 2, 2018 at 12:48 PM Jerry Zhang <zhangjerry@xxxxxxxxxx> wrote:
>
> Commit 1b9ba000 ("Allow function drivers to pause control
> transfers") states that USB_GADGET_DELAYED_STATUS is only
> supported if data phase is 0 bytes.
>
> It seems that when the length is not 0 bytes, there is no
> need to explicitly delay the data stage since the transfer
> is not completed until the user responds. However, when the
> length is 0, there is no data stage and the transfer is
> finished once setup() returns, hence there is a need to
> explicitly delay completion.
>
> This manifests as the following bugs:
>
> Prior to 946ef68ad4e4 ('Let setup() return
> USB_GADGET_DELAYED_STATUS'), when setup is 0 bytes, ffs
> would require user to queue a 0 byte request in order to
> clear setup state. However, that 0 byte request was actually
> not needed and would hang and cause errors in other setup
> requests.
>
> After the above commit, 0 byte setups work since the gadget
> now accepts empty queues to ep0 to clear the delay, but all
> other setups hang.
>
> Fixes: 946ef68ad4e4 ("Let setup() return USB_GADGET_DELAYED_STATUS")
> Signed-off-by: Jerry Zhang <zhangjerry@xxxxxxxxxx>
> ---
>
> This patch used to be in a set, but is being submitted
> standalone for the next 4.18 rc.
>
> drivers/usb/gadget/function/f_fs.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
> index 4e47e8c58067..a6868f936c78 100644
> --- a/drivers/usb/gadget/function/f_fs.c
> +++ b/drivers/usb/gadget/function/f_fs.c
> @@ -3281,7 +3281,7 @@ static int ffs_func_setup(struct usb_function *f,
> __ffs_event_add(ffs, FUNCTIONFS_SETUP);
> spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
>
> - return USB_GADGET_DELAYED_STATUS;
> + return creq->wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
> }
>
> static bool ffs_func_req_match(struct usb_function *f,
> --
> 2.18.0.399.gad0ab374a1-goog
>
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