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I am running Raspberry Pi OS on said raspberry Pi 4. I can mount the S24U to the pi by connecting directly to it via USB-C cable with no issues. I can read the file system and use scrcpy etc.

The enhancement I want to make is to plug a powered USB-C hub into the S24U so I can use some additional peripherals connected to the phone at the same time as the Pi.

The additional peripherals work in this setup, but I lose connection to the S24U (cannot see file system or use scrcpy etc. on the Pi)

Is there something additional I must do to complete this setup? Is it even possible?

Thanks in advance for any ideas or input.

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  • I think you are using the RPi as USB Host and the S24 as USB Device and likely USB/MTP. Then you want the use the S24 as a USB Host for more peripherals of unknown protocols? USB is flexible. However I do not think you can use the same device both as a USB Host and USB Device simultaneously. Actually, I don't think you can have more than 1 USB Host. Further, I think USB Hubs only operate in one direction. They are plugged into the USB Host using a plug and USB Devices are plugged into the USB Hubs using a socket.
    – st2000
    Commented Sep 19 at 3:34

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Don't keep doing this.

As st2000 says, you cannot have multiple hosts connected to a hub meaningfully, because a slave/peripheral device can only be in use by one host at a time. For example, if one of the devices is a keyboard, when you type should that go to the phone, or to the Pi, or both? There are hub devices intended for keyboard sharing, but they include a switch. Hubs also generally have a specific host port indicated because of this.

When you connect the phone to the Pi, the phone is acting as a slave device and the Pi is the host. Unless you configure the Pi appropriately, it cannot be the other way around. And if what you want to do is access the filesystem etc. on the phone from the Pi, the phone must be acting as a slave device, which it will not do when plugged into a hub this way if it can access other devices as peripheral.

You can force the phone to act as a slave by putting it in MTP mode but then it will not be able to access the other devices, so there is no point to the hub except as a power supply.

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