Date:   Sat, 9 Feb 2019 23:47:36 +0100 (CET)
From:   Stefan Wahren <stefan.wahren@i2se.com>
To:     Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Cc:     Felix Fietkau <nbd@nbd.name>,
        Stanislaw Gruszka <sgruszka@redhat.com>,
        Doug Anderson <dianders@chromium.org>,
        Minas Harutyunyan <hminas@synopsys.com>,
        linux-wireless <linux-wireless@vger.kernel.org>,
        linux-usb@vger.kernel.org
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Subject: Re: [BUG] mt76x0u: Probing issues on Raspberry Pi 3 B+
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Hi Lorenzo,

> Lorenzo Bianconi <lorenzo.bianconi@redhat.com> hat am 9. Februar 2019 um 21:33 geschrieben:
> 
> 
> >
> > Hi Lorenzo,
> >
> > > Lorenzo Bianconi <lorenzo.bianconi@redhat.com> hat am 9. Februar 2019 um 19:46 geschrieben:
> > >
> > >
> > > >
> > > > Hi,
> > > >
> > > > as already reported here [1], that there are probing issues of mt76 using TP-Link Archer T2UH (wifi USB dongle) on Raspberry Pi 3 B+.
> > > >
> > > > I retested it with recent linux-next 20190208 (aarch64 defconfig + enabling mt76 driver) and got the following output after plugin the wifi dongle:
> > > >
> > > > [   29.778524] usb 1-1.3: new high-speed USB device number 6 using dwc2
> > > > [   31.794581] usb 1-1.3: reset high-speed USB device number 6 using dwc2
> > > > [   31.919916] mt76x0u 1-1.3:1.0: ASIC revision: 76100002 MAC revision: 76502000
> > > > [   32.304412] dwc2 3f980000.usb: dwc2_update_urb_state(): trimming xfer length
> > > > [   32.325724] dwc2 3f980000.usb: dwc2_update_urb_state(): trimming xfer length
> > > > [   32.346866] dwc2 3f980000.usb: dwc2_update_urb_state(): trimming xfer length
> > > > [   33.410559] mt76x0u 1-1.3:1.0: firmware upload timed out
> > > > [   33.435458] mt76x0u: probe of 1-1.3:1.0 failed with error -110
> > > > [   33.454829] usbcore: registered new interface driver mt76x0u
> > > >
> > > > I took the firmware files from here [2].
> > > >
> > > > Btw there is another issue, if i disconnect the wifi dongle during probe i'm getting a endless flood of the following output:
> > > >
> > > > mt76x0u 1.1.3:1.0: rx urb failed: -71
> > > >
> > > > Any chance to narrow down these issues?
> > >
> > > Hi Stefan,
> > >
> > > could you please test the following series:
> > > https://patchwork.kernel.org/cover/10764453/
> >
> > yeah this fixed the probing timeout and the driver will probe successful. AFAIK the dwc2 host mode doesn't support scatter-gather yet.
> >
> 
> Hi Stefan,
> 
> is the dongle working properly now? Are you able to connect to your AP?

i successful tested STA mode with 2.4 GHz and 5 GHz.

> 
> > > Applying this series I am able to connect to my home AP using an Asus
> > > USB-AC51 (mt76x0u) connected to a Raspberry Pi 3 B+.
> > > I am running rpi-5.0.y branch of https://github.com/raspberrypi/linux.git
> >
> > The foundation kernel uses a different USB driver called dwc-otg which make use of FIQ.
> >
> > Okay, now we only need to find a solution for the "rx urb failed" flood ;-)
> 
> Does it happen just if you remove the dongle during probe?

I also see those messages while disconnecting after a successful probe but in this case the messages stopps after a few seconds. In case of a disconnect while probing the flood never ends. It looks like the rx tasklet is triggered forever.

Stefan

> 
> Regards,
> Lorenzo
>