Re: [PATCH v2 2/2] Revert "usb: dwc3: Don't switch OTG -> peripheral if extcon is present"

From: Ferry Toth
Date: Thu Oct 06 2022 - 08:29:04 EST


On 06-10-2022 04:12, Thinh Nguyen wrote:
On Wed, Oct 05, 2022, Ferry Toth wrote:


Does the failure only happen the first time host is initialized? Or can
it recover after switching to device then back to host mode?

I can switch back and forth and device mode works each time, host mode remains

Probably the failure happens if some step(s) in dwc3_core_init() hasn't

tusb1210 is a phy driver right? The issue is probably because we didn't
initialize the phy yet. So, I suspect placing dwc3_get_extcon() after
initializing the phy will probably solve the dependency problem.

You can try something for yourself or I can provide something to test
later if you don't mind (maybe next week if it's ok).

Yes, the code move I mentioned above "moves dwc3_get_extcon() until after
dwc3_core_init() but just before dwc3_core_init_mode(). AFAIU initially
dwc3_get_extcon() was called from within dwc3_core_init_mode() but only for
case USB_DR_MODE_OTG. So with this change order of events is more or less
unchanged" solves the issue.

I saw the experiment you did from the link you provided. We want to also
confirm exactly which step in dwc3_core_init() was needed.

Ok. I first tried the code move suggested by Andrey (didn't work). Then after reading the actual code I moved a bit further.

This move was on top of -rc6 without any reverts. I did not make additional changes to dwc3_core_init()

So current v6.0 has: dwc3_get_extcon - dwc3_get_dr_mode - ... - dwc3_core_init - .. - dwc3_core_init_mode (not working)

I changed to: dwc3_get_dr_mode - dwc3_get_extcon - .. - dwc3_core_init - .. - dwc3_core_init_mode (no change)

Then to: dwc3_get_dr_mode - .. - dwc3_core_init - .. - dwc3_get_extcon - dwc3_core_init_mode (works)

.. are what I believe for this issue irrelevant calls to dwc3_alloc_scratch_buffers, dwc3_check_params and dwc3_debugfs_init.