Re: [PATCH] usb: dwc3: gadget: Inform system of suspended state

[Mike Looijmans <mike.looijmans@topic.nl>]

[-- Attachment #1: Type: text/plain, Size: 2597 bytes --]

On 05-06-2024 01:06, Thinh Nguyen wrote:
> Hi,
>
> On Tue, Jun 04, 2024, Mike Looijmans wrote:
>> On 04-06-2024 03:03, Thinh Nguyen wrote:
>>> Hi,
>>>
>>> On Mon, Jun 03, 2024, Mike Looijmans wrote:
>>>> When disconnecting the USB cable on an LS1028 device, nothing happens
>>>> in userspace, which keeps thinking everything is still up and running.
>>>> Turns out that the DWC3 controller only sends DWC3_DEVICE_EVENT_SUSPEND
>>>> in that case, and not a DWC3_DEVICE_EVENT_DISCONNECT as one would
>>>> expect. As a result, sysfs attribute "state" remains "configured"
>>>> until something resets it.
>>>>
>>>> Forward the "suspended" state to sysfs, so that the "state" at least
>>>> changes into "suspended" when one removes the cable, and hence also
>>>> matches the gadget's state when really suspended.
>>> On disconnection, did you see disconnect interrupt? If so, it should
>>> transition to USB_STATE_NOATTACHED. This change doesn't seem to directly
>>> address your issue. Can you provide the driver tracepoints?
>> The device doesn't issue a disconnect event, I didn't have tracing enabled
>> in the kernel but added some dev_info() calls to determine what was going
>> on. Added this to dwc3_process_event_entry():
>>
>> dev_info(dwc->dev, "event: 0x%x type=0x%x", event->raw, event->type.type);
>>
>> When disconnecting the cable from the host, I see this:
>>
>> [   50.841411] dwc3 3110000.usb: event: 0x6084 type=0x42
>> [   50.841457] dwc3 3110000.usb: event: 0x4086 type=0x43
>> [   50.841494] dwc3 3110000.usb: event: 0x6084 type=0x42
>> [   50.841534] dwc3 3110000.usb: event: 0x4086 type=0x43
>> [   50.841571] dwc3 3110000.usb: event: 0x4086 type=0x43
>> [   52.650990] dwc3 3110000.usb: event: 0x30601 type=0x0
>>
>> The "0x4086" and "0x6084" messages are endpoint events that occur all the
>> time while connected. The last event is the "suspend" one. After that, total
>> silence.
>>
>> If you need traces, please point me to a description on how to obtain them.
>>
>>
> Let me know if you run into issues following this instructions to
> capture the tracepoints:
> https://docs.kernel.org/driver-api/usb/dwc3.html#required-information
I've attached the traces as a tarball. Hope it survives.

At the start, the USB is up and running (and doing ethernet+mass 
storage). I saved the trace after pulling the USB cable.


-- 
Mike Looijmans
System Expert

TOPIC Embedded Products B.V.
Materiaalweg 4, 5681 RJ Best
The Netherlands

T: +31 (0) 499 33 69 69
E: mike.looijmans@topic.nl
W: www.topic.nl



[-- Attachment #2: dwc3-trace-ls1028.tar.gz --]
[-- Type: application/gzip, Size: 3073 bytes --]