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From: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
To: Mathias Nyman <mathias.nyman@linux.intel.com>,
	Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
	Felipe Balbi <balbi@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
	Mathias Nyman <mathias.nyman@intel.com>
Cc: John Youn <John.Youn@synopsys.com>
Subject: Re: [PATCH v2 6/7] usb: xhci: Workaround lost disconnect port status
Date: Thu, 29 Apr 2021 01:00:37 +0000
Message-ID: <8bcce1fc-70ba-91d6-5671-eaa9dec255e6@synopsys.com> (raw)
In-Reply-To: <37b09a1a-d2f7-c152-0850-20215822ff1d@linux.intel.com>

Mathias Nyman wrote:
> On 10.4.2021 3.47, Thinh Nguyen wrote:
>> If an eSS device with active periodic transfers is disconnected from the
>> DWC_usb31 (v1.90a and prior) host controller at root port, the host
>> controller may not detect a disconnection. By active transfers, it
>> means that the endpoint is not in flow control, and there are active
>> Transfer Descriptors available for the host to initiate transfers to the
>> endpoint. This issue can occur if the endpoint periodic interval is in
>> 2ms, 4ms, or 8ms.
>>
>> In addition, the host controller will not be able to detect a new device
>> connection while the disconnection is not processed. The controller will
>> set the link state of the affected port to eSS_INACTIVE.
>>
>> To workaround this, have the xHCI driver polls for the eSS root port
>> status every 2 seconds. If eSS_INACTIVE state is detected, initiate a
>> fake connection change to stop all the active endpoints and start
>> polling for new connection change.
> 
> 
> If this only happens with active periodic transfers can we skip the polling
> and check port link state in the transfer error event handling?
> 
> Like in the previous case there the periodic device was behind a hub.
> 

No, this occurs with an application with interrupt endpoint (but also
affects isoc). We may not get a transfer completion event to notify to
check for port link state. I hope this change is not too intrusive since
we can reuse a timer polling for port status.

Thanks,
Thinh


  reply index

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-09  1:41 [PATCH 0/6] usb: Set quirks for xhci/dwc3 host mode Thinh Nguyen
2021-04-09  1:41 ` [PATCH 1/6] usb: xhci: Move quirks definitions to common usb header Thinh Nguyen
2021-04-09  6:50   ` Greg Kroah-Hartman
2021-04-09  8:01     ` Thinh Nguyen
2021-04-09 16:26   ` kernel test robot
2021-04-09 19:54   ` kernel test robot
2021-04-09  1:42 ` [PATCH 2/6] usb: xhci: Check for blocked disconnection Thinh Nguyen
2021-04-09  1:42 ` [PATCH 3/6] usb: xhci: Workaround undercalculated BW for fullspeed BI Thinh Nguyen
2021-04-09  1:42 ` [PATCH 4/6] usb: xhci: Rename Compliance mode timer quirk Thinh Nguyen
2021-04-09  1:42 ` [PATCH 5/6] usb: xhci: Workaround lost disconnect port status Thinh Nguyen
2021-04-09  1:42 ` [PATCH 6/6] usb: dwc3: host: Set quirks base on version Thinh Nguyen
2021-04-09  6:53   ` Greg Kroah-Hartman
2021-04-09  8:01     ` Thinh Nguyen
2021-04-09 13:22       ` Greg Kroah-Hartman
2021-04-10  0:44         ` Thinh Nguyen
2021-04-10  0:46 ` [PATCH v2 0/7] usb: Set quirks for xhci/dwc3 host mode Thinh Nguyen
2021-04-10  0:46   ` [PATCH v2 1/7] usb: xhci: Move quirks definitions to common usb header Thinh Nguyen
2021-04-10  0:46   ` [PATCH v2 2/7] usb: xhci: Move xhci-plat header " Thinh Nguyen
2021-04-10  0:47   ` [PATCH v2 3/7] usb: xhci: Check for blocked disconnection Thinh Nguyen
2021-04-27 13:08     ` Mathias Nyman
2021-04-27 22:30       ` Thinh Nguyen
2021-04-28 13:32         ` Mathias Nyman
2021-04-29  0:54           ` Thinh Nguyen
2021-04-10  0:47   ` [PATCH v2 4/7] usb: xhci: Workaround undercalculated BW for fullspeed BI Thinh Nguyen
2021-04-28 11:57     ` Mathias Nyman
2021-04-10  0:47   ` [PATCH v2 5/7] usb: xhci: Rename Compliance mode timer quirk Thinh Nguyen
2021-04-10  0:47   ` [PATCH v2 6/7] usb: xhci: Workaround lost disconnect port status Thinh Nguyen
2021-04-28 13:48     ` Mathias Nyman
2021-04-29  1:00       ` Thinh Nguyen [this message]
2021-04-10  0:47   ` [PATCH v2 7/7] usb: dwc3: host: Set quirks base on version Thinh Nguyen
2021-04-19 21:07   ` [PATCH v2 0/7] usb: Set quirks for xhci/dwc3 host mode Thinh Nguyen

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