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Original question:

TUSB8041: Trouble rediscovering ports after uplugging from USB backplane

TUSB8041: cannot rediscovering the devices at the downstream port, after unplug and plug in again

kwxsp
Prodigy 95 points
Part Number: TUSB8041

cannot rediscovering the devices at the downstream port, after unplug and then plug in again;

test:

1. after the linux system is up, plugin a devce to the onboard hub tusb8041, can not discover the device pluged in.

2. before power up the board system, plug in a device to onboard hub tusb8041 downstream port,  after the linux is up, use "lsusb" the device can be found. then do operation: "unplug the device and plug in again", it can not be discovered again, then in linux system, rescan usb devices again(use "echo 0 /sys/bus/usb/devices/1-3/authorized; echo 1 /sys/bus/usb/devices/1-3/authorized;" 1-3 is the hub tusb8041), the device can be found again;  or reset tusb8041 hardware(short grst pin to gnd), the device plugin can also be found again. 

3. use a hub standalone plug in to a usb port without tusb8041 in the same system board, any device plug in to the standalone hub, everything is ok( any time any plug and unplug operation, or  plug in a device after linux system is up or before system power up).

(ps:sorry for my poor english)

  • 0
    TI__Guru 60870 points

    Hello Kwxsp,

    It sounds like there may be a Linux driver issue where it is not configuring the control status endpoint of the hub properly and the TUSB8041 is not able to report port changes.  Do you see the same behavior with USB 2.0 devices and USB 3.0 devices?

    Regards,

    JMMN

  • 0 in reply to JMMN
    Prodigy 95 points

    hi ,

    The tested device is a mouse(USB2.0). I think it may not be a linux driver issue, because i previous post:

    ===============================

    3. use a hub standalone plug in to a usb port without tusb8041 in the same system board, any device plug in to the standalone hub, everything is ok( any time any plug and unplug operation, or  plug in a device after linux system is up or before system power up).

    ===============================

    the standalone hub is used some other brand ic for office general use.

    or the tusb have some special driver settings for the control status endpoint?

    and now we have cut off the usb 3.0 rx tx line(remove the coupling capacitors), and with some linux driver related modified.

    any suggestion?

    thank you.

  • 0 in reply to JMMN
    Prodigy 95 points

    hi JMMN,

    how the tusb8041 report device attachment?

    the tusb8041 up stream ic is an ULPI ic, it may not have feature of "UTMI+ Level 3: decode a pre-amble packet"

  • 0 in reply to kwxsp
    TI__Guru 60870 points

    Which Linux kernel is being used?

  • 0 in reply to kwxsp
    TI__Guru 60870 points

    You marked this thread is resolved, is it?

  • 0 in reply to JMMN
    Prodigy 95 points

    yes! may be it is a hardware issue as i previous posted, "the ULPI does not decoder a preamble packet". we have begin to pick another ULPI IC.