Re: [PATCH] usb: musb: fix enumeration after resume

Re: [PATCH] usb: musb: fix enumeration after resume

[Tony Lindgren]

* Andreas Kemnade <andreas-cLv4Z9ELZ06ZuzBka8ofvg@public.gmane.org> [180127 08:34]:
> On dm3730 there are enumeration problems after resume.
> Investigation led to the cause that the MUSB_POWER_SOFTCONN
> bit is not set. If it was set before suspend (because it
> was enabled via musb_pullup()), it is set in
> musb_restore_context() so the pullup is enabled. But then
> musb_start() is called which overwrites MUSB_POWER and
> therefore disables MUSB_POWER_SOFTCONN, so no pullup is
> enabled and the device is not enumerated.

I just gave this patch a quick try and things seem to behave
for me from PM point of view:

Tested-by: Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>

Unrelated to this patch, I also noticed that we now somehow
higher idle power consumption initially when musb modules are
loaded. It used to idle after that but now to get things to
idle I had to plug and unplug a USB device once to the musb
port.

Regards,

Tony
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH] usb: musb: fix enumeration after resume

[Andreas Kemnade]

[-- Attachment #1: Type: text/plain, Size: 1410 bytes --]

Hi,

On Tue, 6 Feb 2018 10:47:25 -0800
Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org> wrote:

> * Andreas Kemnade <andreas-cLv4Z9ELZ06ZuzBka8ofvg@public.gmane.org> [180127 08:34]:
> > On dm3730 there are enumeration problems after resume.
> > Investigation led to the cause that the MUSB_POWER_SOFTCONN
> > bit is not set. If it was set before suspend (because it
> > was enabled via musb_pullup()), it is set in
> > musb_restore_context() so the pullup is enabled. But then
> > musb_start() is called which overwrites MUSB_POWER and
> > therefore disables MUSB_POWER_SOFTCONN, so no pullup is
> > enabled and the device is not enumerated.  
> 
> I just gave this patch a quick try and things seem to behave
> for me from PM point of view:
> 
> Tested-by: Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>
> 
> Unrelated to this patch, I also noticed that we now somehow
> higher idle power consumption initially when musb modules are
> loaded. It used to idle after that but now to get things to
> idle I had to plug and unplug a USB device once to the musb
> port.
> 
Hmm, I have seen this effect with some earlier kernels but not with
4.15. My observation is that current consumption went down again after
a modprobe g_ether and ifconfig usb0 up

I was loading modules piece by piece and waited 10s after each and then
measured.

Regards,
Andreas

[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

Re: [PATCH] usb: musb: fix enumeration after resume

[Bin Liu]

On Tue, Feb 06, 2018 at 10:47:25AM -0800, Tony Lindgren wrote:
> * Andreas Kemnade <andreas@kemnade.info> [180127 08:34]:
> > On dm3730 there are enumeration problems after resume.
> > Investigation led to the cause that the MUSB_POWER_SOFTCONN
> > bit is not set. If it was set before suspend (because it
> > was enabled via musb_pullup()), it is set in
> > musb_restore_context() so the pullup is enabled. But then
> > musb_start() is called which overwrites MUSB_POWER and
> > therefore disables MUSB_POWER_SOFTCONN, so no pullup is
> > enabled and the device is not enumerated.
> 
> I just gave this patch a quick try and things seem to behave
> for me from PM point of view:
> 
> Tested-by: Tony Lindgren <tony@atomide.com>

Thanks for testing it.

Regards,
-Bin.