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libusb not showing devices

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kkrpeq:
Hello,

I am trying to use piCore on a RPi 02W to perform usb communication with an usb 2.0 device.
However, libusb was not able to find any device I connected to the RPi. The output of "sudo lsusb" shows only the built in usb hub,  and not my device:

Protocol spec without prior Class and Subclass spec at line 23179
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

"sudo lsusb -t" and "dmesg" also show only the hub.

Am I missing something?

curaga:
No, any drivers missing would not affect lsusb or dmesg. You have a physical problem with the connection, power, or usb device.

kkrpeq:
I have been doing some tests with two usb devices, namely DeviceA and DeviceB. I know they both work because I can use them on Mac and Windows.

If I plug in DeviceA, the RPi recognizes it as expected, and the device works properly.
If I plug in DeviceB, the RPi stops recognizing usb devices. Even if I remove DeviceB and insert DeviceA, it will not recognize anything.

Upon further inspection, it seems the RPi is cutting off the power to the usb devices whenever I insert (or try to use) DeviceB. I am verifying this by using this command:


--- Code: ---cat /sys/devices/platform/soc/3f980000.usb/buspower
Bus Power = 0x0

--- End code ---

I can turn the power on by writing 0x1 to buspower:


--- Code: ---echo 0x1 > /sys/devices/platform/soc/3f980000.usb/buspower
--- End code ---

But it will turn off again if DeviceB is connected.
I have tried using an external/exclusive power supply for DeviceB, but it still didn't work.
Is there any option in config.txt, bootcode, or something similar that might help?

Rich:
Hi kkrpeq

--- Quote from: kkrpeq on April 15, 2022, 12:58:28 AM --- ... I have tried using an external/exclusive power supply for DeviceB, but it still didn't work. ...
--- End quote ---
Not sure what you mean by that.

Try placing a powered hub between  DeviceB  and your  RPi .

kkrpeq:

--- Quote from: Rich on April 15, 2022, 01:28:21 AM ---
--- Quote from: kkrpeq on April 15, 2022, 12:58:28 AM --- ... I have tried using an external/exclusive power supply for DeviceB, but it still didn't work. ...
--- End quote ---
Not sure what you mean by that.

--- End quote ---

I used an usb adapter that has an auxiliary power inlet. The +5V supplied to the usb device does not come from the RPi, instead it comes from another power supply.
It is like a powered hub, but without the "hub" part. Here is a picture of the adapter:




--- Quote from: Rich on April 15, 2022, 01:28:21 AM ---Try placing a powered hub between  DeviceB  and your  RPi .

--- End quote ---

I just tried using an actual powered hub. Strangely enough, the hub shows the same behaviour as DeviceB: when I connect the hub to the RPi (even if the hub has no devices connected to it), Bus Power is automatically set to 0x0.

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