imx6q usb disconnect issue

[angelo_d]

Dear all,

i have this scenario in a similar sabrelite custom board (without usb hub onboard chip), and kernel 3,14.

USB connector ---> USB external 2.0 HUB (non powered)

On the hub i have a small keyboard and filesystem stick.

Consumption on VBUS is, as above, 80mA. VBUS at connector is 4,98V.

I connect now 2 USB powered spekers on the hub (low volume).

VBUS moves to  4,96, current to 140mA abt. But i get a disconnect message about the

usb filesystem stick from the kernel.

localhost login: 
usb 2-1: USB disconnect, device number 2
usb 2-1.1: USB disconnect, device number 3

I don't have any evidence of VBUS issues, board can source 1050mA.

Seems a disconenct due to the data line signals.

There could be some driver issue afayk ? Or it could be some host register to set better ?

Every help is really appreciated.

Thanks,

angelo

[angelo_d]

Hi Igor,

thanks for great support.

No we never seen any FAULT signal generated from overcurrent.

Well, we have set a 1050mA current limit, and this disconnect messages comes sometime (one per day can happen) at 500mA abt, or even less, and the reason is not clear. Voltage is 4,9 abt, likely, above the USB spec limit.

Even for low consume devices, as usb touch, we get sometime the disconnect.

We have verified the disconnect being issued without a signalled (irq) disconnect event. So we think we have some hardware issue, like  some d +/- lines issue and the communication get broken. Maybe some termination issue or the like.

If any suggestion,  very welocme.

Thanks

angelo

[igorpadykov]

Hi Angelo

one can test if this is caused by noise:

use short usb cable, better filter usb supply or

use external power supply for hub.

Best regards

igor

[igorpadykov]

Hi Angelo

one can check overcurrent warn signal usb_otg_oc, on Sabre board spf-27392

generated by U515 MIC2026.

Best regards

igor

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