[sane-devel] Canon on Raspberry Pi

[Mac Goever]

Hi Sean,

thanks for the analysis. I was a little unspecific about the dmesg:
The disconnects are explainable by me unplugging the cable. This means
all the disconnects are explainable. The resets are not, but I
suspected them to be normal. My Ubuntu Laptop does not do the reset.
The Power supply is a modded 450W ATX supply I modded. I had the
experience with wall warts, so I chose the big cannon for testing ;)

I will do more testing on the power side anyway.

Cheerio

Martin

On Tue, May 19, 2020 at 2:03 AM Sean Greenslade <sean at seangreenslade.com> wrote:
>
> On Mon, May 18, 2020 at 08:18:36PM +0200, Mac Goever wrote:
> > Hi Sean,
> >
> > yes, I can do that. Here are some log entries. I suspected the device
> > to disappear right after the "reset" entry. But this is not the case.
> > It might also disappear some seconds after the event.
> >
> > ---
> > [  328.405481] usb 1-1.4: new high-speed USB device number 5 using dwc_otg
> > [  328.537196] usb 1-1.4: New USB device found, idVendor=05e3,
> > idProduct=0605, bcdDevice= 6.0b
> > [  328.537212] usb 1-1.4: New USB device strings: Mfr=0, Product=1,
> > SerialNumber=0
> > [  328.537221] usb 1-1.4: Product: USB2.0 Hub
> > [  328.538152] hub 1-1.4:1.0: USB hub found
> > [  328.538449] hub 1-1.4:1.0: 4 ports detected
> > [  328.675475] usb 1-1.2: reset high-speed USB device number 4 using dwc_otg
> > [  334.252684] usb 1-1.2: USB disconnect, device number 4
> > [  338.085480] usb 1-1.4.3: new high-speed USB device number 6 using dwc_otg
> > [  338.216965] usb 1-1.4.3: New USB device found, idVendor=04a9,
> > idProduct=190e, bcdDevice= 7.04
> > [  338.216981] usb 1-1.4.3: New USB device strings: Mfr=1, Product=2,
> > SerialNumber=0
> > [  338.216991] usb 1-1.4.3: Product: CanoScan
> > [  338.217000] usb 1-1.4.3: Manufacturer: Canon
>
> Up to here, this is a normal USB enumeration.
>
> > [  348.615487] usb 1-1.4.3: reset high-speed USB device number 6 using dwc_otg
>
> But here, 10 seconds after enumerating, we see an unexpected reset.
>
> > [  781.257336] usb 1-1.4.3: USB disconnect, device number 6
>
> And ~7 minutes later, the device disconnects.
>
> > [  787.105074] usb 1-1.4.3: new high-speed USB device number 7 using dwc_otg
> > [  787.236590] usb 1-1.4.3: New USB device found, idVendor=04a9,
> > idProduct=190e, bcdDevice= 7.04
> > [  787.236620] usb 1-1.4.3: New USB device strings: Mfr=1, Product=2,
> > SerialNumber=0
> > [  787.236630] usb 1-1.4.3: Product: CanoScan
> > [  787.236639] usb 1-1.4.3: Manufacturer: Canon
>
> Another normal enumeration.
>
> > [  791.095083] usb 1-1.4.3: reset high-speed USB device number 7 using dwc_otg
>
> And another unexpected reset after a few seconds.
>
> > [  981.232218] usb 1-1.4.3: USB disconnect, device number 7
>
> This time, the disconnect happened in ~3 minutes.
>
> > [  991.254819] usb 1-1.4.3: new high-speed USB device number 8 using dwc_otg
> > [  991.386331] usb 1-1.4.3: New USB device found, idVendor=04a9,
> > idProduct=190e, bcdDevice= 7.04
> > [  991.386348] usb 1-1.4.3: New USB device strings: Mfr=1, Product=2,
> > SerialNumber=0
> > [  991.386358] usb 1-1.4.3: Product: CanoScan
> > [  991.386367] usb 1-1.4.3: Manufacturer: Canon
> > [ 2101.778329] usb 1-1.4.3: USB disconnect, device number 8
> > [ 2279.596695] usb 1-1.4: USB disconnect, device number 5
> > [78022.354395] usb 1-1.2: new high-speed USB device number 9 using dwc_otg
> > [78022.486136] usb 1-1.2: New USB device found, idVendor=05e3,
> > idProduct=0605, bcdDevice= 6.0b
> > [78022.486152] usb 1-1.2: New USB device strings: Mfr=0, Product=1,
> > SerialNumber=0
> > [78022.486161] usb 1-1.2: Product: USB2.0 Hub
> > [78022.487104] hub 1-1.2:1.0: USB hub found
> > [78022.487402] hub 1-1.2:1.0: 4 ports detected
>
> A USB hub was plugged in. Notice that this device doesn't ever have a
> reset, so it's behaving correctly.
>
> > [78022.804366] usb 1-1.2.3: new high-speed USB device number 10 using dwc_otg
> > [78022.935681] usb 1-1.2.3: New USB device found, idVendor=04a9,
> > idProduct=190e, bcdDevice= 7.04
> > [78022.935690] usb 1-1.2.3: New USB device strings: Mfr=1, Product=2,
> > SerialNumber=0
> > [78022.935695] usb 1-1.2.3: Product: CanoScan
> > [78022.935699] usb 1-1.2.3: Manufacturer: Canon
>
> The scanner was plugged in, presumably into the hub.
>
> > [78032.084421] usb 1-1.2.3: reset high-speed USB device number 10 using dwc_otg
>
> And our friend the reset is back.
>
> In short, the issue is almost certainly in hardware.
>
> My prime suspects would be:
> - Insufficient power supply stability. This refers to both current
>   capacity and voltage sag, the latter of which can be hard to test.
>   Additionally, a real 10 A 5 V power supply should be fairly large,
>   comparable to a medium-size laptop brick. If your 10 A supply is a
>   wall wart, I would be very suspicious of it.
>
>   If you have a good multimeter, I would suggest measuring the 5 V rail
>   on the Pi's GPIO headers while you have the scanner plugged in.
>   Anything below 4.9 V would be concerning.
>
> - Flaky USB cable. Try another one if you have it, the shorter the
>   better.
>
> - Flaky USB port. Try the other ports on the Pi just to see.
>
> - Flaky powered USB hub / poor quality hub power supply. Cheap hubs
>   often have equally cheap power supplies.
>
> - Damaged USB subsystem on Pi. This one is unlikely, but it may be worth
>   testing other USB devices (e.g. a thumb drive) on your Pi and see if
>   you get similar issues.
>
> Hopefully this helps narrow down the issue.
>
> --Sean
>