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From: Jeffery Miller <jefferymiller@google.com>
Date: Thu, 9 May 2024 16:09:16 -0500
Message-ID: <CAAzPG9M+KNowPwkoYo+QftrN3u6zdN1cWq0XMvgS8UBEmWt+0g@mail.gmail.com>
Subject: Re: [PATCH v2] net: usb: ax88179_178a: avoid writing the mac address
 before first reading
To: jtornosm@redhat.com
Cc: davem@davemloft.net, Eric Dumazet <edumazet@google.com>, inventor500@vivaldi.net, 
	jarkko.palviainen@gmail.com, kuba@kernel.org, linux-kernel@vger.kernel.org, 
	linux-usb@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, 
	stable@vger.kernel.org, vadim.fedorenko@linux.dev
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Hello Jos=C3=A9,

I'm testing on the 6.6 kernel with a "0b95:1790 ASIX Electronics Corp.
AX88179 Gigabit Ethernet" device.
after applying commit 56f78615bcb1 ("net: usb: ax88179_178a: avoid
writing the mac address before first reading")
the network will no longer work after brining the device down.

After plugging in the device, it generally will work with ifconfig:
$ ifconfig eth0 <ip address>
However, if I then try bringing the devcie down and back up, it no longer w=
orks.
$ ifconfig eth0 down
$ ifconfig eth0  <ip address>
$ ethtool eth0 | grep detected
  Link detected: no

The link will continue to report as undetected.

If I revert 56f78615bcb1 the device will work after bringing it down
and back up.

If I build at commit d7a319889498 ("net: usb: ax88179_178a: avoid two
consecutive device resets") and its
parent d7a319889498^ these also work.

Is this something you have seen before with your test devices?

Regards,
Jeff