Confusing USB device conflict

[Mark Millard]

> On 2020-Jun-6, at 15:38, bob prohaska <fbsd at www.zefox.net> wrote:
> 
> Just got a disk, adapter and usb3 hub for use with
> freebsd-arm. When it's connected to a Pi2 running 12-stable,
> the console reports
> 
> login: ugen0.6: <GenesysLogic USB2.0 Hub> at usbus0
> uhub2 on uhub1
> uhub2: <GenesysLogic USB2.0 Hub, class 9/0, rev 2.00/92.24, addr 6> on usbus0
> uhub2: MTT enabled
> uhub2: 4 ports with 4 removable, self powered
> smsc0: warning: Failed to read register 0x114
> smsc0: warning: MII is busy
> smsc0: warning: Failed to read register 0x114
> smsc0: warning: MII is busy
> smsc0: warning: Failed to read register 0x114
> smsc0: warning: MII is busy
> smsc0: warning: Failed to read register 0x114
> smsc0: warning: MII is busy
> (da0:umass-sim0:0:0:0): READ(10). CDB: 28 00 02 06 20 50 00 00 30 00 
> 
> Things then go from bad to worse, ending with

Does this happen with FreeBSD head? It looked like there
was a late 2019 check-in that was related to a context
that involved the above types of messages on a RPi*. If
you are lucky, may be there is something someone could
MFC back into 12 that would help. (I do not know the
details or if what I saw really would help if head
works okay.)

> (da0:umass-sim0:0:0:0): Periph destroyed
> umass0: detached
> ugen0.5: <FTDI USB - Serial> at usbus0 (disconnected)
> uftdi0: at uhub1, port 4, addr 5 (disconnected)
> uftdi0: detached
> ugen0.6: <GenesysLogic USB2.0 Hub> at usbus0 (disconnected)
> uhub2: at uhub1, port 5, addr 6 (disconnected)
> uhub2: detached
> uhub1: detached
> ugen0.2: <Unknown > at usbus0 (disconnected)
> Jun  6 15:20:00 www syslogd: /var/log/cron: Device not configured
> vm_fault: pager read error, pid 924 (sendmail)
> vm_fault: pager read error, pid 927 (sendmail)
> vm_fault: pager read error, pid 930 (sendmail)
> vm_fault: pager read error, pid 933 (sendmail)
> vm_fault: pager read error, pid 936 (sendmail)
> 
> AFAIK, smsc is a (not-present) network device. Perhaps a case of
> mistaken identity? I've seen complaints from smsc0 before, but
> not lately.

On a RPi3 here (omitted text indicated with ". . ."):

# devinfo 
nexus0
  ofwbus0
    psci0
    simplebus0
      . . .
      bcm283x_dwcotg0
        usbus0
          uhub0
            uhub1
              smsc0
                miibus0
                  smscphy0
              uhub3
                umass0
              uhub2
                ukbd0
                uhid0
                ums0
      . . .
    ofw_clkbus0
    . . .
  cryptosoft0

(Context: head -r360311 based)

In the above, uhub3 is my external, powered, USB3
capable hub that the USB3 SSD is on that holds
FreeBSD. (USB2 compatible devices.)

# usbconfig show_ifdrv
. . .
ugen0.2: <vendor 0x0424 product 0x9514> at usbus0, cfg=0 md=HOST spd=HIGH (480Mbps) pwr=SAVE (2mA)
ugen0.2.0: uhub1: <vendor 0x0424 product 0x9514, class 9/0, rev 2.00/2.00, addr 2>
ugen0.3: <vendor 0x0424 product 0xec00> at usbus0, cfg=0 md=HOST spd=HIGH (480Mbps) pwr=ON (2mA)
ugen0.3.0: smsc0: <vendor 0x0424 product 0xec00, rev 2.00/2.00, addr 3>
ugen0.7: <GenesysLogic USB2.0 Hub> at usbus0, cfg=0 md=HOST spd=HIGH (480Mbps) pwr=SAVE (100mA)
ugen0.7.0: uhub3: <GenesysLogic USB2.0 Hub, class 9/0, rev 2.00/90.20, addr 7>
ugen0.8: <OWC Envoy Pro mini> at usbus0, cfg=0 md=HOST spd=HIGH (480Mbps) pwr=ON (0mA)
ugen0.8.0: umass0: <OWC Envoy Pro mini, class 0/0, rev 2.10/1.00, addr 8>
. . .

uhub1 and smsc0 are internal the the RPi3,
smsc being for the Ethernet interface (based on
looking around that is what it appeared to be
anyway).

An interesting implication is that the Ethernet and the
external USB ports on the RPi3* share bandwidth via
uhub1 and uhub0.

> FWIW, when connected to a Pi3B+ running Raspberry Pi Buster, the hub,
> adapter and disk are recognized correctly, but dmesg reports:
> The driver for the USB controller dwc_otg_hcd does not support scatter-gather which is
> required by the UAS driver. Please try an other USB controller if you wish to use UAS. 
> There's no crash, and it looks like the device file is created, though I haven't
> tried to talk with it yet.

https://www.raspberrypi.org/forums/viewtopic.php?f=28&t=245931 documents:

QUOTE
Prior to Pi 4, the USB host controller software did not support DMA
scatter-gather operations. As a result of this limitation, the USB
Attached SCSI (UAS) driver was not enabled. . . .
All UAS drives must support mass-storage as a fallback option. . . .
END QUOTE

So the lack of UAS support for the context should not mean
lack of mass-storage support.

===
Mark Millard
marklmi at yahoo.com
( dsl-only.net went
away in early 2018-Mar)