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Message-ID: <be8904bd-71ea-4ae1-b0bc-9170461fd0d9@gmail.com>
Date: Thu, 11 Apr 2024 22:52:36 +0200
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Subject: Re: [PATCH v4] usb: gadget: u_ether: Replace netif_stop_queue with
 netif_device_detach
To: Andy Shevchenko <andriy.shevchenko@intel.com>,
 Hardik Gajjar <hgajjar@de.adit-jv.com>
Cc: gregkh@linuxfoundation.org, s.hauer@pengutronix.de, jonathanh@nvidia.com,
 linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
 quic_linyyuan@quicinc.com, paul@crapouillou.net, quic_eserrao@quicinc.com,
 erosca@de.adit-jv.com
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 <f25283fc-4550-4725-960b-2ea783fd62e1@gmail.com>
 <aeee83d8-dee3-42ed-b705-988b17800721@gmail.com>
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 <ZhgSPCq6sVejRjbj@smile.fi.intel.com>
Content-Language: en-US
From: Ferry Toth <fntoth@gmail.com>
In-Reply-To: <ZhgSPCq6sVejRjbj@smile.fi.intel.com>
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Hi

Op 11-04-2024 om 18:39 schreef Andy Shevchenko:
> On Thu, Apr 11, 2024 at 04:26:37PM +0200, Hardik Gajjar wrote:
>> On Wed, Apr 10, 2024 at 08:37:42PM +0300, Andy Shevchenko wrote:
>>> On Sun, Apr 07, 2024 at 10:51:51PM +0200, Ferry Toth wrote:
>>>> Op 05-04-2024 om 13:38 schreef Hardik Gajjar:
> ...
>
>>>> Exactly. And this didn't happen before the 2 patches.
>>>>
>>>> To be precise: /sys/class/net/usb0 is not removed and it is a link, the link
>>>> target /sys/devices/pci0000:00/0000:00:11.0/dwc3.0.auto/gadget.0/net/usb0 no
>>>> longer exists
>> So, it means that the /sys/class/net/usb0 is present, but the symlink is
>> broken. In that case, the dwc3 driver should recreate the device, and the
>> symlink should become active again

Yes, on first enabling gadget (when device mode is activated):

root@yuna:~# ls /sys/devices/pci0000:00/0000:00:11.0/dwc3.0.auto/gadget.0/
driver  net  power  sound  subsystem  suspended  uevent

Then switching to host mode:

root@yuna:~# ls /sys/devices/pci0000:00/0000:00:11.0/dwc3.0.auto/gadget.0/
ls: cannot access 
'/sys/devices/pci0000:00/0000:00:11.0/dwc3.0.auto/gadget.0/': No such 
file or directory

Then back to device mode:

root@yuna:~# ls /sys/devices/pci0000:00/0000:00:11.0/dwc3.0.auto/gadget.0/
driver  power  sound  subsystem  suspended  uevent

net is missing. But, network functions:

root@yuna:~# ping 10.42.0.1
PING 10.42.0.1 (10.42.0.1): 56 data bytes

Mass storage device is created and removed each time as expected.

>> I have the dwc3 IP base usb controller, Let me check with this patch and
>> share result here.  May be we need some fix in dwc3
Would have been nice if someone could test on other controller as well. 
But another instance of dwc3 is also very welcome.
> It's quite possible, please test on your side.
> We are happy to test any fixes if you come up with.
>