Re: MUSB: unreliable OTG detection in host mode

[Kevin Hilman <khilman@mvista.com>]

David Brownell wrote:
>> On 2430, I've noticed that using the driver built in OTG mode, the
>> detection of devices in host-mode is unreliable.
> 
> Unreliable in what way(s)?

Meaning it sometimes detects connected devices and sometimes not.
Sometimes a reboot and another try helps.  But with recent git it seems
to never detect devices.

> 
>> 	Building the driver in
>> only host mode doesn't have any problems with the same devices connected.
>>
>> I load the musb_hdrc module, then the g_zero module to initiate OTG
>> detection.
>>
>> If my board is connected as a gadget, this works just fine, but if my
>> board is the host and I have devices connected, the detection doesn't
>> work reliably.  In the past it seemed it would work most of the time,
>> but with the latest kernel, it doesn't seem to work at all.
> 
> This somewhat resembles a problem I've not tracked down, whereby
> the 2420 + TUSB6010-EVM, in OTG mode, seems to recieve garbage
> when reading descriptors from the high speed hub I usually like
> to connect as a root device.
>
> DaVinci didn't seem to have any such issues...
> 

I haven't tested DaVinci in OTG mode since on the EVM board I have, you
have to move a jumper to switch between the two.

Kevin