From: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
To: Felipe Balbi <balbi@kernel.org>,
Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>
Cc: John Youn <John.Youn@synopsys.com>
Subject: Re: [PATCH 1/3] usb: dwc3: gadget: Properly handle failed kick_transfer
Date: Fri, 13 Mar 2020 19:50:20 +0000 [thread overview]
Message-ID: <c17da637-abf1-75b0-e8bf-737958773e8e@synopsys.com> (raw)
In-Reply-To: <874kusgwuz.fsf@kernel.org>
Hi Felipe,
Felipe Balbi wrote:
> Hi Thinh,
>
> Thinh Nguyen <Thinh.Nguyen@synopsys.com> writes:
>> If dwc3 fails to issue START_TRANSFER/UPDATE_TRANSFER command, then we
>> should properly end an active transfer and give back all the started
>> requests. However if it's for an isoc endpoint, the failure maybe due to
>> bus-expiry status. In this case, don't give back the requests and wait
>> for the next retry.
>>
>> Fixes: 72246da40f37 ("usb: Introduce DesignWare USB3 DRD Driver")
>> Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
> could you give some details regarding when does this happen?
>
So, here are the scenarios in which dwc3_send_gadget_ep_cmd() may return
a negative errno:
* -EAGAIN: Isoc bus-expiry status
As you already know, this occurs when we try to schedule isoc too
late. If we're going to retry the request, don't unmap it.
* -EINVAL: No resource due to issuing START_TRANSFER to an already
started endpoint
This happens generally because of SW programming error
* -ETIMEDOUT: Polling for CMDACT timed out
This should not happen unless the controller is dead or in some bad
state
BR,
Thinh
next prev parent reply other threads:[~2020-03-13 19:50 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-13 2:18 [PATCH 0/3] usb: dwc3: gadget: Improve isoc starting mechanism Thinh Nguyen
2020-03-13 2:18 ` [PATCH 1/3] usb: dwc3: gadget: Properly handle failed kick_transfer Thinh Nguyen
2020-03-13 14:20 ` Felipe Balbi
2020-03-13 19:50 ` Thinh Nguyen [this message]
2020-03-15 8:48 ` Felipe Balbi
2020-03-16 0:33 ` Thinh Nguyen
2020-03-16 7:03 ` Felipe Balbi
2020-03-16 19:06 ` Thinh Nguyen
2020-03-29 7:52 ` Felipe Balbi
2020-03-29 23:14 ` Thinh Nguyen
2020-03-13 2:18 ` [PATCH 2/3] ute: dwc3: gadget: Store resource index of start cmd Thinh Nguyen
2020-03-13 2:18 ` [PATCH 3/3] usb: dwc3: gadget: Issue END_TRANSFER to retry isoc transfer Thinh Nguyen
2020-03-13 14:38 ` Felipe Balbi
2020-03-13 20:01 ` Thinh Nguyen
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