Date:   Thu, 9 Feb 2023 11:18:07 +0100
From:   Sascha Hauer <s.hauer@pengutronix.de>
To:     Paul Cercueil <paul@crapouillou.net>
Cc:     linux-usb@vger.kernel.org,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org, kernel@pengutronix.de
Subject: Re: [PATCH 1/2] usb: gadget: u_ether: Do not make UDC parent of the
 net device
Message-ID: <20230209101807.GO10447@pengutronix.de>
References: <20221104131031.850850-1-s.hauer@pengutronix.de>
 <20221104131031.850850-2-s.hauer@pengutronix.de>
 <f2a4f9847617a0929d62025748384092e5f35cce.camel@crapouillou.net>
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Hi Paul,

On Wed, Feb 01, 2023 at 01:32:51PM +0000, Paul Cercueil wrote:
> Hi Sascha, Greg,
> 
> I have a breakage in 6.2-rc* that I eventually bisected to this commit,
> on a Ingenic SoC (using the jz4740 musb driver) with ECM or RNDIS
> configured through gadgetfs.
> 
> When plugging the board to my PC, the USB network interface is
> recognized, but 'ip link' sees it as 'NO-CARRIER'. With this commit
> reverted on v6.2-rc5, everything works fine.

I don't have this hardware available. I just tried with a i.MX hardware
and it works as expected. I have no idea where the jz4740 musb could
behave differently.

Here's exactly what I did:

mkdir -p /sys/kernel/config/usb_gadget/mygadget
cd /sys/kernel/config/usb_gadget/mygadget
mkdir -p configs/c.1/strings/0x409
echo "C1:Composite Device" > configs/c.1/strings/0x409/configuration
mkdir -p functions/ecm.usb0
ln -s functions/ecm.usb0 configs/c.1/
echo "ci_hdrc.0" > UDC

Did you do something differently apart from the "ci_hdrc.0" of course?

BTW when you say 'NO-CARRIER' is it on the PC side, board side, or
both?

It would be great if we could sort this out, but if not I am fine with
reverting this patch. I guess this topic will come back to my desk
sooner or later then

Sascha

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