linux-kernel - Re: [RFT PATCH 0/4] usb: dwc2: Turn on uframe sched everywhere

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Date:   Wed, 11 Jul 2018 13:29:08 +0200 (CEST)
From:   Stefan Wahren <stefan.wahren@...e.com>
To:     Doug Anderson <dianders@...omium.org>
Cc:     Jerome Brunet <jbrunet@...libre.com>,
        Bruno Herrera <bruherrera@...il.com>,
        Minas Harutyunyan <hminas@...opsys.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-usb@...r.kernel.org, Zhangfei Gao <zhangfei.gao@...aro.org>,
        LKML <linux-kernel@...r.kernel.org>, balbi@...nel.org,
        grigor.tovmasyan@...opsys.com
Subject: Re: [RFT PATCH 0/4] usb: dwc2: Turn on uframe sched everywhere

Hi Doug,

[add Felipe and Grigor]

> Doug Anderson <dianders@...omium.org> hat am 10. Juli 2018 um 17:21 geschrieben:
> 
> 
> Hi,
> 
> On Tue, Jul 10, 2018 at 6:57 AM, Stefan Wahren <stefan.wahren@...e.com> wrote:
> > Hi Doug,
> >
> > since Stephen isn't BCM2835 maintainer anymore, please keep me in the loop.
> 
> Sorry for missing you.  :(  I wonder if you should add yourself to the
> MAINTAINERS file as a reviewer for dwc2 so you can get CCed always?

i don't think this is necessary and my USB knowledge is to little. I've setup a jenkins to catch regressions from linux-next. This is currently sufficient.

> 
> 
> > I'm not sure how to test this. Is there some kind of test scenario (don't
> > have a USB analyzer)?
> 
> I guess it'll depend on what USB devices you have sitting around.  The
> more USB devices you have plugged in then the more likely the dumb
> scheduler will get things wrong and a device won't like you.  You
> should also see significant compatibility improvements when you have
> low/full speed devices plugged into high speed USB hubs.
> 
> IIRC when testing I did things like:
> - In general, try to have lots of things plugged in.
> - Plug many different keyboards / mice in.  See if keys are dropped /
> mouse is jerky.
> - Try USB audio (ideally full speed, not high speed).  How is the audio?
> - If you're brave, try a USB webcam.  How is the video?

Thanks for the hints. The BCM2835 only have 8 EP, so my test setup isn't big:

1x Rasberry Pi 2 (with onboard ethernet SMSC95xx via USB)
1x keyboard connected to the Pi directly
1x external powered 7 port HUB (1x mice and 1x USB serial adapter)

/:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=dwc2/1p, 480M
    |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/5p, 480M
        |__ Port 1: Dev 3, If 0, Class=Vendor Specific Class, Driver=smsc95xx, 480M
        |__ Port 2: Dev 4, If 0, Class=Human Interface Device, Driver=usbhid, 1.5M
        |__ Port 2: Dev 4, If 1, Class=Human Interface Device, Driver=usbhid, 1.5M
        |__ Port 4: Dev 5, If 0, Class=Hub, Driver=hub/4p, 480M
            |__ Port 1: Dev 6, If 0, Class=Hub, Driver=hub/4p, 480M
                |__ Port 1: Dev 7, If 0, Class=Human Interface Device, Driver=usbhid, 1.5M
                |__ Port 4: Dev 8, If 0, Class=Vendor Specific Class, Driver=, 12M

But even in this simple scenario, your patch #1 is an improvement.

Without the hub connected and without your patch
or with the hub (and the 2 devices) connected and with your patch the SMSC95xx works properly:

[   45.668254] smsc95xx 1-1.1:1.0 eth0: hardware isn't capable of remote wakeup
[   47.146506] smsc95xx 1-1.1:1.0 eth0: link up, 100Mbps, full-duplex, lpa 0xCDE1

But with the hub (and the 2 devices) connected and without your patch the SMSC95xx driver has timeouts and in the result the RPi won't get an IP from my router:

[   20.408622] smsc95xx 1-1.1:1.0 eth0: hardware isn't capable of remote wakeup
[   20.807821] Adding 102396k swap on /var/swap.  Priority:-2 extents:1 across:102396k SS
[   26.401346] smsc95xx 1-1.1:1.0 eth0: Failed to read reg index 0x00000114: -110
[   26.401360] smsc95xx 1-1.1:1.0 eth0: Error reading MII_ACCESS
[   26.401371] smsc95xx 1-1.1:1.0 eth0: MII is busy in smsc95xx_mdio_read
[   26.401387] smsc95xx 1-1.1:1.0 eth0: Failed to read MII_BMSR
[   31.441429] smsc95xx 1-1.1:1.0 eth0: Failed to read reg index 0x00000114: -110
[   31.441454] smsc95xx 1-1.1:1.0 eth0: Error reading MII_ACCESS
[   31.441465] smsc95xx 1-1.1:1.0 eth0: MII is busy in smsc95xx_mdio_read
[   31.441481] smsc95xx 1-1.1:1.0 eth0: link reset failed (-110) usbnet usb-3f980000.usb-1.1, smsc95xx USB 2.0 Ethernet
[   36.481359] smsc95xx 1-1.1:1.0 eth0: Failed to read reg index 0x00000114: -110
[   36.481372] smsc95xx 1-1.1:1.0 eth0: Error reading MII_ACCESS
[   36.481383] smsc95xx 1-1.1:1.0 eth0: MII is busy in smsc95xx_mdio_read
[   36.481402] smsc95xx 1-1.1:1.0 eth0: link reset failed (-110) usbnet usb-3f980000.usb-1.1, smsc95xx USB 2.0 Ethernet
[   41.521345] smsc95xx 1-1.1:1.0 eth0: Failed to read reg index 0x00000114: -110
[   41.521358] smsc95xx 1-1.1:1.0 eth0: Error reading MII_ACCESS
[   41.521369] smsc95xx 1-1.1:1.0 eth0: MII is busy in smsc95xx_mdio_read
[   41.521387] smsc95xx 1-1.1:1.0 eth0: link reset failed (-110) usbnet usb-3f980000.usb-1.1, smsc95xx USB 2.0 Ethernet
[   46.561349] smsc95xx 1-1.1:1.0 eth0: Failed to read reg index 0x00000114: -110
[   46.561363] smsc95xx 1-1.1:1.0 eth0: Error reading MII_ACCESS
[   46.561374] smsc95xx 1-1.1:1.0 eth0: MII is busy in smsc95xx_mdio_read
[   46.561393] smsc95xx 1-1.1:1.0 eth0: link reset failed (-110) usbnet usb-3f980000.usb-1.1, smsc95xx USB 2.0 Ethernet
[   59.441375] smsc95xx 1-1.1:1.0 eth0: Failed to read reg index 0x00000118: -110
[   59.441389] smsc95xx 1-1.1:1.0 eth0: Error reading MII_DATA
[   59.441405] smsc95xx 1-1.1:1.0 eth0: link reset failed (-110) usbnet usb-3f980000.usb-1.1, smsc95xx USB 2.0 Ethernet
[   64.545268] smsc95xx 1-1.1:1.0 eth0: Failed to read reg index 0x00000114: -110
[   64.545285] smsc95xx 1-1.1:1.0 eth0: Error reading MII_ACCESS
[   64.545297] smsc95xx 1-1.1:1.0 eth0: MII is busy in smsc95xx_mdio_read
[   64.545324] smsc95xx 1-1.1:1.0 eth0: link reset failed (-110) usbnet usb-3f980000.usb-1.1, smsc95xx USB 2.0 Ethernet

So you can have my

Tested-by: Stefan Wahren <stefan.wahren@...e.com>

for the bcm patch.

> 
> 
> If you're trying a USB webcam w/ dwc2, maybe add in patches mentioned
> in <https://bugs.chromium.org/p/chromium/issues/detail?id=820961>

Interesting

Best regards
Stefan

> 
> 
> -Doug