On Mon, 2020-07-20 at 03:44 +0000, Peter Chen wrote:

quoted

On Wed, 2020-07-15 at 00:51 +0000, Peter Chen wrote:

quoted

quoted

The Toradex Colibri iMX6ULL board has a special USB hardware
design.
With runtime-pm enabled USB reset itself continuously.
Furthermore
the OTG port is also not enumerating devices if the Chipidea IP
is
in runtime sleep mode and a device or host gets plugged in.

Hi Philippe,

You may describe the detail what's the special USB hardware design
for
your board,

If I only knew the root-cause of that problem - unfortunately I
don't.
That's also why I have such a hard time to describe it.

quoted

and why it causes the problem, and why disable runtime pm could
fix
this issue, then,

I cannot provide the 'why' part yet. I'll try something more and
hope I can provide
you guys with the exact description.

quoted

the other users could know if it could apply to their platforms or
not
in future.

I only found out about it because you were pointing me in that
direction. I debugged
for hours now and didn't came to the root-cause of the issue. I
think to really
understand it I would need to know much more about the Chipidea IP.

I'll get back to you guys with a proposal for a new description.

Philippe, is it possible to share your USB hardware design at 6ULL?

It's actually pretty simple: We have on USB_OTG1_VBUS a 1uF capacitor
and +3.0V on VDD_USB_CAP together with 100n and 10u bypass caps. Now the
big problem is that the driver can not detect the 5V on VBUS signal.

I tried to 'inject' 5V to that pin last week and things got really
better with runtime-pm. But I still thinks disabling it for our board
would make sense.

I'll send a new description today where I try to point to VBUS signal
not connected.

Philippe

And how ci_hdrc_gadget_connect is called when the runtime pm is
disabled?

Thanks,
Peter
 

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