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TUSB8041A: Downstream devices inconsistently enumerating

Part Number: TUSB8041A

Hello,

My customer is seeing issues with TUSB8041A and enumeration of downstream devices. When they power on the board with no devices connected, they see the hub enumerate in USBView but when they connect devices to the downstream ports they do not see any devices enumerate. However, if they power on the board with a device already connected to a downstream port they see it enumerate and can use the device. If they then connect devices to other downstream ports those will also enumerate, but if they disconnect all devices and try to reconnect a device it will not enumerate.

One interesting note that may be relevant is that if USB Selective Suspend is disabled in PC Advanced Power Settings, everything works fine. So it seems like for some reason the PC thinks the hub is going to sleep/not being used. Have you seen this issue and do you know of a potential fix?

Thanks,

Michael

  • Hi Michael,

    What operating system are they using?  And which driver version on the host and the hub?  Are they seeing this with both USB 2.0 downstream devices and USB 3.0 downstream devices?  It sounds like the remote wake from the hub is being ignored, but this is something that is tested pretty heavily so I'll need a bit more information on the system to help debug.  Also if they can provide the usbview screenshots, that'd be useful.

    Regards,

    JMMN