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

[H. Nikolaus Schaller]

Hi Michael,

> Am 04.02.2018 um 11:55 schrieb Michael Nazzareno Trimarchi <michael at amarulasolutions.com>:
> 
> 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?

it is essentially a copy&paste from BeagleBoard XM.

Schematics of the GTA04 are here:

	http://projects.goldelico.com/p/gta04-main/downloads/48/

USB PHY is on page 9.

BR,
Nikolaus

> 
> michael
> 
> 
>> Regards,
>> Andreas
> 
> 
> 
> -- 
> | Michael Nazzareno Trimarchi                     Amarula Solutions BV |
> | COO  -  Founder                                      Cruquiuskade 47 |
> | +31(0)851119172                                 Amsterdam 1018 AM NL |
> |                  [`as] http://www.amarulasolutions.com               |
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