Problem with self-powered USB hubs

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sfd
Posts: 4
Joined: Mon Dec 12, 2016 10:00 am

Problem with self-powered USB hubs

Thu Nov 16, 2017 12:21 pm

Hello,

We are having an issue with self-powered USB hubs on our custom, Sama5D4-based board.

If we plug the board to hubs which are not themselves connected to a host, we often get flooded with "ODD" log messages (https://github.com/linux4sam/linux-at91 ... d45758abd3 - we are still using the 4.4 branch). Contrary to the comment, this is not exactly harmless because those messages can greatly delay the Linux boot-up sequence (journald apparently can't cope with that many messages).

This does not happen with non self-powered hubs.

If I understand the code correctly, these messages are caused by "ENDRESET" interrupts. I'd like to confirm this interrupt correspond to the section 7.1.7.3 Reset signaling of the USB 1.1 specification:
A hub signals reset to a downstream port by driving an extended SE0 at the port. After the reset is
removed, the device will be in the Default state (refer to Section 9.1).
I suspect an electric problem around D+ and D- that causes the USB subsystem to see a reset condition.
sfd
Posts: 4
Joined: Mon Dec 12, 2016 10:00 am

Re: Problem with self-powered USB hubs

Tue Nov 28, 2017 10:16 am

Bump.

Could someone from Microchip at least confirm or deny that the ENDRESET interrupt is the result of a USB reset signaling described in the spec?
blue_z
Location: USA
Posts: 1560
Joined: Thu Apr 19, 2007 10:15 pm

Re: Problem with self-powered USB hubs

Tue Nov 28, 2017 10:03 pm

For a Microchip response, try contacting Tech Support directly.

Regards

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