[Letux-kernel] power management problems in ehci-omap

[Andreas Kemnade]

Hi,

On Sun, 4 Feb 2018 09:43:45 +0100
Michael Nazzareno Trimarchi <michael at amarulasolutions.com> wrote:

> Hi Andreas
> 
> On Sun, Feb 4, 2018 at 9:38 AM, Andreas Kemnade <andreas at kemnade.info> wrote:
> > On Sun, 4 Feb 2018 00:10:50 +0100
> > Michael Nazzareno Trimarchi <michael at amarulasolutions.com> wrote:
> >  
> >> Hi
> >>
> >> On Sun, Feb 4, 2018 at 12:03 AM, Andreas Kemnade <andreas at kemnade.info> wrote:  
> >> > Hi,
> >> >
> >> > I booted a 4.15 kernel without udev and loaded modules piece by piece to analyze
> >> > pm problems. modprobe ehci-omap increases current by around 35mA and
> >> > also rmmod ehci-omap does not let it go down at all.
> >> >
> >> > I expect that removing hardware does the same thing  
> > nonsense sentence from me, was to tired. I would expect that removing the modules
> > properly powers down the device.  
> >> >
> >> > Also suspend current increases by around 15mA if that module is loaded.
> >> > I tested with having everything disabled which is attached to that usb bus.
> >> >  
> >>
> >> Do you have an LTE connected to the usb?
> >>  
> > Yes, there is a UMTS modem attached, but it was off during the tests.
> > It did not enumerate on the modem.
> >  
> 
> Just to understand if the suspend current drop was connected to the
> suspend of lte modem on your side.
> So you don't have anything connected on usb bus?
> 
Suspend current is increased when the ehci-omap module is loaded
in comparison to the state. I tested with the modem disabled, so there
is nothing on the bus. Increased suspend current is one thing,
current_before_modprobe_ehci_omap != current_after_rmmod_ehci_omap.

I am testing with init=some_testscript.sh, so no userspace
is doing strange things. No module autoload or something.

Regards,
Andreas