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Message-ID: <20210420010846.GA6408@nchen>
Date: Tue, 20 Apr 2021 09:08:47 +0800
From: Peter Chen <peter.chen@...nel.org>
To: Pawel Laszczak <pawell@...ence.com>
Cc: balbi@...nel.org, gregkh@...uxfoundation.org,
ruslan.bilovol@...il.com, jbrunet@...libre.com,
linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
kurahul@...ence.com
Subject: Re: [PATCH 1/2] usb: gadget: f_uac2: Stop endpoint before enabling
it.
On 21-04-19 09:50:53, Pawel Laszczak wrote:
> From: Pawel Laszczak <pawell@...ence.com>
>
> Patch adds disabling endpoint before enabling it during changing
> alternate setting. Lack of this functionality causes that in some
> cases uac2 queue the same request multiple time.
> Such situation can occur when host send set interface with
> alternate setting 1 twice.
>
> Signed-off-by: Pawel Laszczak <pawell@...ence.com>
> ---
> drivers/usb/gadget/function/f_uac2.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/usb/gadget/function/f_uac2.c b/drivers/usb/gadget/function/f_uac2.c
> index 9cc5c512a5cd..7d20a9d8a1b4 100644
> --- a/drivers/usb/gadget/function/f_uac2.c
> +++ b/drivers/usb/gadget/function/f_uac2.c
> @@ -890,17 +890,17 @@ afunc_set_alt(struct usb_function *fn, unsigned intf, unsigned alt)
> if (intf == uac2->as_out_intf) {
> uac2->as_out_alt = alt;
>
> + u_audio_stop_capture(&uac2->g_audio);
> +
> if (alt)
> ret = u_audio_start_capture(&uac2->g_audio);
> - else
> - u_audio_stop_capture(&uac2->g_audio);
> } else if (intf == uac2->as_in_intf) {
> uac2->as_in_alt = alt;
>
> + u_audio_stop_playback(&uac2->g_audio);
> +
> if (alt)
> ret = u_audio_start_playback(&uac2->g_audio);
> - else
> - u_audio_stop_playback(&uac2->g_audio);
> } else {
> dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
> return -EINVAL;
To avoid this, you may use prm->ep_enabled to judge if the endpoint has
already enabled.
--
Thanks,
Peter Chen
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