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

Michael Nazzareno Trimarchi michael at amarulasolutions.com
Sun Feb 4 11:55:02 CET 2018


Hi Andreas

On Sun, Feb 4, 2018 at 11:50 AM, Andreas Kemnade <andreas at kemnade.info> wrote:
> 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.
>

How many port are configured and how is the phy part connected to the
ehci controller?
Can you point me the schematic page?

michael


> Regards,
> Andreas



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| Michael Nazzareno Trimarchi                     Amarula Solutions BV |
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