From: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
To: Peter Chen <peter.chen@nxp.com>, linux-usb@vger.kernel.org
Cc: linux-imx@nxp.com, stable@vger.kernel.org, Jun Li <jun.li@nxp.com>
Subject: Re: [PATCH 1/1] usb: chipidea: udc: workaround for endpoint conflict issue
Date: Mon, 27 May 2019 12:02:18 +0300 [thread overview]
Message-ID: <64ff033b-7f7e-ad91-ac06-73ebd8565286@cogentembedded.com> (raw)
In-Reply-To: <20190527074222.42970-1-peter.chen@nxp.com>
On 27.05.2019 10:42, Peter Chen wrote:
> An endpoint conflict occurs when the USB is working in device mode
> during an isochronous communication. When the endpointA IN direction
> is an isochronous IN endpoint, and the host sends an IN token to
> endpointA on another device, then the OUT transaction may be missed
> regardless the OUT endpoint number. Generally, this occurs when the
> device is connected to the host through a hub and other devices are
> connected to the same hub.
>
> The affected OUT endpoint can be either control, bulk, isochronous, or
> an interrupt endpoint. After the OUT endpoint is primed, if an IN token
> to the same endpoint number on another device is received, then the OUT
> endpoint may be unprimed (cannot be detected by software), which causes
> this endpoint to no longer respond to the host OUT token, and thus, no
> corresponding interrupt occurs.
>
> There is no good workaround for this issue, the only thing the software
> could do is numbering isochronous IN from the highest endpoint since we
> have observed most of device number endpoint from the lowest.
>
> Cc: <stable@vger.kernel.org> #v3.14+
> Cc: Jun Li <jun.li@nxp.com>
> Signed-off-by: Peter Chen <peter.chen@nxp.com>
> ---
> drivers/usb/chipidea/udc.c | 24 ++++++++++++++++++++++++
> 1 file changed, 24 insertions(+)
>
> diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
> index 829e947cabf5..411d387a45c9 100644
> --- a/drivers/usb/chipidea/udc.c
> +++ b/drivers/usb/chipidea/udc.c
> @@ -1622,6 +1622,29 @@ static int ci_udc_pullup(struct usb_gadget *_gadget, int is_on)
> static int ci_udc_start(struct usb_gadget *gadget,
> struct usb_gadget_driver *driver);
> static int ci_udc_stop(struct usb_gadget *gadget);
> +
> +
> +/* Match ISOC IN from the highest endpoint */
> +static struct
Um, please break the line before the function's type is fully described.
> +usb_ep *ci_udc_match_ep(struct usb_gadget *gadget,
> + struct usb_endpoint_descriptor *desc,
> + struct usb_ss_ep_comp_descriptor *comp_desc)
> +{
> + struct ci_hdrc *ci = container_of(gadget, struct ci_hdrc, gadget);
> + struct usb_ep *ep;
> + u8 type = desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK;
> +
> + if ((type == USB_ENDPOINT_XFER_ISOC) &&
> + (desc->bEndpointAddress & USB_DIR_IN)) {
Please add 1 more tab here, so that this line doesn't blend with the
following statement.
> + list_for_each_entry_reverse(ep, &ci->gadget.ep_list, ep_list) {
> + if (ep->caps.dir_in && !ep->claimed)
> + return ep;
> + }
> + }
> +
> + return NULL;
> +}
> +
> /**
> * Device operations part of the API to the USB controller hardware,
> * which don't involve endpoints (or i/o)
[...]
MBR, Sergei
next prev parent reply other threads:[~2019-05-27 9:02 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-27 7:42 [PATCH 1/1] usb: chipidea: udc: workaround for endpoint conflict issue Peter Chen
2019-05-27 9:02 ` Sergei Shtylyov [this message]
2019-05-27 9:44 ` Peter Chen
2019-05-27 11:49 ` Sergei Shtylyov
2019-05-30 6:45 Peter Chen
2019-05-30 8:22 ` Sergei Shtylyov
2019-05-30 8:48 ` Peter Chen
2019-06-17 1:49 [PATCH 0/1] usb: chipidea: fixes for v5.2 Peter Chen
2019-06-17 1:49 ` [PATCH 1/1] usb: chipidea: udc: workaround for endpoint conflict issue Peter Chen
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