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

[Ferry Toth]

Hi,

Op 10-10-2022 om 23:35 schreef Andrey Smirnov:
> On Mon, Oct 10, 2022 at 1:52 PM Ferry Toth <fntoth@xxxxxxxxx> wrote:
> > Hi
> >
> > Op 10-10-2022 om 13:04 schreef Ferry Toth:
> > > Hi
> > >
> > > On 10-10-2022 07:02, Andrey Smirnov wrote:
> > > > On Fri, Oct 7, 2022 at 6:07 AM Ferry Toth <fntoth@xxxxxxxxx> wrote:
> > > > > On 07-10-2022 04:11, Thinh Nguyen wrote:
> > > > > > On Thu, Oct 06, 2022, Ferry Toth wrote:
> > > > > > > Hi
> > > > > > >
> > > > > > > On 06-10-2022 04:12, Thinh Nguyen wrote:
> > > > > > > > On Wed, Oct 05, 2022, Ferry Toth wrote:
> > > > > > > > > Hi,
> > > > > > > > >
> > > > > > > > >         Thanks!
> > > > > > > > >
> > > > > > > > >         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
> > > > > > > > > dead.
> > > > > > > > Ok.
> > > > > > > >
> > > > > > > > >         Probably the failure happens if some step(s) in
> > > > > > > > > dwc3_core_init() hasn't
> > > > > > > > >         completed.
> > > > > > > > >
> > > > > > > > >         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.
> > > > > > Right. Thanks for narrowing it down. There are still many steps in
> > > > > > dwc3_core_init(). We have some suspicion, but we still haven't
> > > > > > confirmed
> > > > > > the exact cause of the failure. We can write a proper patch once we
> > > > > > know
> > > > > > the reason.
> > > > > If you would like me to test your suspicion, just tell me what to do
> > > > > :-)
> > > >
> > > > OK, Ferry, I think I'm going to need clarification on specifics on
> > > > your test setup. Can you share your kernel config, maybe your
> > > > "/proc/config.gz", somewhere? When you say you are running vanilla
> > > > Linux, do you mean it or do you mean vanilla tree + some patch delta?
> > >
> > > For v6.0 I can get the exacts tonight. But earlier I had this for v5.17:
> > >
> > > https://github.com/htot/meta-intel-edison/blob/master/meta-intel-edison-bsp/recipes-kernel/linux/linux-yocto_5.17.bb
> > >
> > >
> > > There are 2 patches referred in #67 and #68. One is related to the
> > > infinite loop. The other is I believe also needed to get dwc3 to work.
> > >
> > > All the kernel config are applied as .cfg.
> > >
> > > Patches and cfs's here:
> > >
> > > https://github.com/htot/meta-intel-edison/tree/master/meta-intel-edison-bsp/recipes-kernel/linux/files
> >
> > Updated Yocto recipe for v6.0 here:
> >
> > https://github.com/htot/meta-intel-edison/blob/honister/meta-intel-edison-bsp/recipes-kernel/linux/linux-yocto_6.0.bb
> >
> > #75-#77 are the 2 reverts from Andy, + one SOF revert (not related to
> > this thread).
>
> Please drop all of this
> https://github.com/htot/meta-intel-edison/blob/honister/meta-intel-edison-bsp/recipes-kernel/linux/linux-yocto_6.0.bb#L69-L77
> and re do the testing. Assuming things are still broken, that's how
> you want to do the bisecting.

I removed 4 patches:
0043b-TODO-driver-core-Break-infinite-loop-when-deferred-p.patch
0044-REVERTME-usb-dwc3-gadget-skip-endpoints-ep-18-in-out.patch
0001-Revert-USB-fixup-for-merge-issue-with-usb-dwc3-Don-t.patch
0001-Revert-usb-dwc3-Don-t-switch-OTG-peripheral-if-extco.patch

and indeed as you expect kernel boots (no infinite loop). However dwc3 
host mode is not working as in your case, device mode works fine (Yocto 
configures a set of gadgets for me).

Just to be sure if I could have bisected without 0043a I added back the 
2 0001-Revert* and indeed I run into the infinite loop with the console 
spitting out continuous:
debugfs: Directory 'dwc3.0.auto' with parent 'ulpi' already present!
tusb1210 dwc3.0.auto.ulpi: error -110 writing val 0x41 to reg 0x80

so yes it seems either 0043b or your patch "usb: dwc3: Don't switch OTG 
-> peripheral if extcon is present" is needed to boot (break the 
infinite loop). But your patch is in my case not sufficient to make host 
mode work.

As I understand it depends a bit on the timing, I might have a different 
initrd (built by Yocto vs. Buildroot). F.i. I see I have 
extcon-intel-mrfld in initrd and dwc3 / phy-tusb1210 built-in.