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TUSB4041I: TUSB4041I Downstream Port Issue

wei xiong zhang
Prodigy 20 points
Part Number: TUSB4041I


Hi,

We use tusb4041i chip on our board, and find a issue.
If the downstream ports does not insert any USB device, and then insert a USB device,  the USB host controller will no longer be able to detect this device.

  • 0
    TI__Guru 60870 points

    Hi,

    If you power on with a device connected on the downstream port, does it work?  If you are using Linux or Android, can you update your build?  The host controller not responding to the interrupt endpoint of the hub was a problem with some very early builds.

    Regards,

    JMMN

  • 0 in reply to JMMN
    Prodigy 20 points

    Thank you for your reply.

    --If you power on with a device connected on the downstream port, does it work? 

    Yes, it can work, and other ports can detect the inserted device.

    --If you are using Linux or Android, can you update your build?  The host controller not responding to the interrupt endpoint of the hub was a problem with some very early builds.

    We use the Linux 4.19,  is a relatively new version. How old is the very early version you said?

    Thanks.

  • 0 in reply to wei xiong zhang
    TI__Guru 60870 points

    Hi Wei,

    It sounds like once the hub goes to suspend mode, the host is not responding to the wakeup when devices are inserted.

    A USB host will typically put a hub in suspend mode when no downstream devices are connected to conserve power and enable the hub for remote wake.  For some reason, it appears that the host is either not enabling remote wake or is not responding to the remote wake from the hub.  

    You can verify that the hub is sending the correct signaling by checking the upstream DP/DM lines, but I don't have a way to confirm the host behavior without a protocol analyzer.  There were Linux builds with a remote wake issue several years ago, but I do not recall the build.

    Regards,

    JMMN