[Letux-kernel] gadget after suspend

[H. Nikolaus Schaller]

Hi,

> Am 16.01.2018 um 07:34 schrieb Andreas Kemnade <andreas at kemnade.info>:
> 
> On Mon, 15 Jan 2018 14:01:16 +0100
> "H. Nikolaus Schaller" <hns at goldelico.com> wrote:
> 
>> Hi,
>> 
>>> Am 15.01.2018 um 07:00 schrieb Andreas Kemnade <andreas at kemnade.info>:
>>> 
>>> Hi,
>>> 
>>> In earlier times, it was helpful to revert this patch to have a
>>> working gadget after suspend. 
>>> 
>>> "PM / Runtime: Don't allow to suspend a device with an active child"
>>> 
>>>   This reverts commit a8636c89648ab12e59d8f3aa667ec76fc96fd643.
>>> 
>>> Now that code changed and I have to find out a better way. 
>>> ifconfig usb0 down ; ifconfig usb0 up from userspace cures the problem.
>>> 
>>> I will of course do more research.  
>> 
>> Ok.
>> 
>> Another thing I usually observe is that this happens if the USB
>> cable is plugged in during boot (it seems not depend on if the
>> USB plugin powers on the device - its suffices to reboot with
>> USB cable still connected).
> 
> connected during which boot phase? During u-boot actions or when the
> kernel boots  I have not seen this kind of problem for
> quite some time.

Almost alway, if connected before u-boot starts (either power-on or reboot
does not matter) but I think it also happens if plugged in too early during
boot. But I have no run a real test case for that so that it is more an anecdotical
observation.

>> 
>> Then I also have to ifdown usb0; ifup usb0 to make it work.
>> 
> ifdown usb0/ifup usb0 does rmmod/modprobe at your setup? 

yes

> That is why I was doing just ifconfig down/up

this does not suffice for me to get a connection.

> 
>> Exactly the same networking setup works on AM335x so this allows
>> to isolate that issue to musb and twl4030-phy.
>> 
> Why? gta04 = musb + omap2430 glue + twl4030-phy
> am335x = musb + am35xx glue + ?

different musb version?

Maybe the "?" is the reason...
Not unlikely.

It is just called "TI PHY" on am33xx and has some control registers.

Well, what also could play a role is USB power detection
(sequence) and signalling (twl interrupt handling).

BR,
Nikolaus

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