Re: BUG with linux 5.9.0 with dwc3 in gadget mode

From: Jack Pham <jackp@codeaurora.org>
To: Ferry Toth <fntoth@gmail.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>,
	"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
	Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
	felipe.balbi@linux.intel.com,
	Heikki Krogerus <heikki.krogerus@linux.intel.com>
Subject: Re: BUG with linux 5.9.0 with dwc3 in gadget mode
Date: Tue, 27 Oct 2020 14:06:48 -0700	[thread overview]
Message-ID: <20201027210648.GB26640@jackp-linux.qualcomm.com> (raw)
In-Reply-To: <0089306e-e2ca-9a53-6ffb-202d028050ce@gmail.com>

Hi Ferry,

On Tue, Oct 27, 2020 at 09:13:31PM +0100, Ferry Toth wrote:
> Hi guys,
> 
> Sorry for messing up the CC list. This was partly thanks to gmane, partly my
> own stupidity. I hope it is complete now.
> 
> I am summarizing the status of this one at the bottom.
> 
> Op 22-10-2020 om 15:43 schreef Andy Shevchenko:
> > On Thu, Oct 22, 2020 at 4:21 PM Thinh Nguyen <Thinh.Nguyen@synopsys.com> wrote:
> > > Ferry Toth wrote:
> > > > Op 21-10-2020 om 21:50 schreef Thinh Nguyen:
> > > > > Ferry Toth wrote:
> > ...
> > 
> > > > > Oops, looks like I can't make it synchronous this way. Can you try
> > > > > Jack's change to the u_audio.c instead?
> > > > Oops indeed goes away with Jack's change, but usb connection goes
> > > > up/down continuously, meaning: my host sees usb network and audio
> > > > device appearing / disappearing.
> > > Ok, thanks for verifying that it went away.
> > > 
> > > > mass_storage device does not appear all.
> > > There are some fixes to dwc3 in kernel mainline. Is it possible to test
> > > this against linux-next?
> > I think the best is to wait for v5.10-rc1 and retest.
> > 
> I looks like there have been at least 3 problems:
> 
> 1) dwc3 was not working in host mode, but not causing an oops. This may have
> been caused by platform changes. Andy has provided a fix for this, dwc3 now
> working in host mode on 5.9
> 
> 2) dwc3 was causing the oops in gadget mode as referenced in this thread.
> The experimental patch from Jack Phan indeed fixes this.
> 
> Code here: https://github.com/edison-fw/linux/commits/eds-acpi-5.9.0

Great, thanks! I'll submit the patch to the list. Is it alright if I
add a Reported-and-tested-by tag from you?

> 3) With the above 2 fixes gadgets work but seem to be powered down (after 15
> sec. or so) and up (after 1 sec.) continuously. No oops, no errors in
> journal. The gadgets I enabled are a network, sound and mass storage. The
> latter stops working due to going up/down quickly. But my host shows
> network/sound appearing/disappearing. Journal of edison shows:
> 
> systemd-networkd[525]: usb0: Gained carrier
> systemd-networkd[525]: usb0: Gained IPv6LL
> systemd-networkd[525]: usb0: Lost carrier
> systemd-networkd[525]: usb0: Gained carrier
> systemd-networkd[525]: usb0: Gained IPv6LL
> systemd-networkd[525]: usb0: Lost carrier
> 
> Any ideas how to proceed are highly welcomed!

I suppose you can start with enabling dwc3 trace events and try to see
what's going on from the gadget side. Please refer to
Documentation/driver-api/usb/dwc3.rst **Reporting Bugs**

Also what happens if you enable the network, sound and mass storage
functions individually rather than all at once (assuming you are using
ConfigFS)?

Jack
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