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DM8168 DVRRDK 3.0:NO support for usb hub hotplug.

SuitJune Young
Genius 3985 points

Hello,TIer.

We wanna use USB of DM8168 in host mode.We connect USB of DM8168 to a usb-hub chip to get file from u-disk which is connected with the usb-hub.

usb(dm8168)<------------->usb_hub<------------>u-disk*4

But,right now,case1:DM8168CCYG4,DVRRDK 3.0

1> Don't connect usb_hub to dm8168's usb before power up the system.

2> Power up the system,;

3> Connect usb_hub to dm8168's usb port,

 The result is that DM8168 cannot recognize the usb_hub.But if we change usb_hub to usb-disk,the result is different-----DM8168 can recognize the usb-disk for hotplug.

What may cause the problem?                                                                           

  • 0
    Genius 3985 points

    Hello,anybody here?

    I found it is a strange thing.

    Sometimes,when the usb-hub hotplug event happens,DM8168 can found usb-hub.And then everything is OK.

    But if after an usb-hub hotplug event,dm8168 don't find hub.Then after that,if connect usb-disk to DM8168, DM8168 can NOT found usb-disk neither.

    Why does this happen?It seems the usb-hub is a usb-killer.

  • 0 in reply to SuitJune Young
    TI__Expert 8250 points

    Hi

    Are you using a bus powered hub? If so the Hub may be drawing more current than can be sustained by the USB port and hence after an over current event, the USB port might be disabled.  Please check with a self-powered USB hub and report back your findings

     

  • 0 in reply to Srirama Govindarajan
    Genius 3985 points

    In what situation,DM8168 can detect the over-current event?

    On our custom board,we use on-board 5V dc/dc to supply 5V power with current to 2A max.And we use this 5V to supply the use port of DM8168 and the usb-hub with no-device connected to usb-hub.I think there is enough power.

    And We make the USB_DRVVBUS NO CONNECT.Just connect 5V directly to our USB-port.

    BR!

  • 0 in reply to Srirama Govindarajan
    Genius 3985 points

    Thank you sir,I think the problem maybe caused by specific hub ic.

    When I use another brand's hub ic,the similar problem disappear.

    BR!

  • 0 in reply to SuitJune Young
    TI__Expert 8250 points

    Hi

    Firstly we need ascertain if the issue is related to OVer current situation. To confirm this, we can enable verbose debug messages in the driver by running the following command

    Before connecting the USB Hub

    # echo D8 > /proc/driver/musb_hdrc.0

    # echo D8 > /proc/driver/musb_hdrc.1

    If the issue occurs(the hub is not connected), you can collect the system status (and share it back on this post)

    # cat /proc/driver.musb_hdrc.0

    #dmesg