linux-kernel - Re: [PATCH 14/16] usb: musb: dsps: add MUSB_DEVCTL

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Message-ID: <51F2BE6F.3010008@linutronix.de>
Date:	Fri, 26 Jul 2013 20:22:39 +0200
From:	Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To:	Bin Liu <binmlist@...il.com>
CC:	linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
	balbi@...com, george.cherian@...com
Subject: Re: [PATCH 14/16] usb: musb: dsps: add MUSB_DEVCTL_SESSION back after
 removal

On 07/26/2013 08:17 PM, Bin Liu wrote:

Hi Bin.

>> In TI 3.2 kernel, the otg_timer() toggles the SESSION bit in
>> OTG_STATE_B_IDLE state. So whenever the ID pin is grounded by
>> connecting a device, the controller will try go into host mode.
>> But I have no idea why your board is in a_idle not b_idle. The toggle
>> does not handle a_idle.
>>
>> Do you use the AM335x GP EVM, not the smaller StarterKit EVM, right?
>> the USB0 port on SK EVM is device only.
>>
>> But anyway, I have not seen any use case which uses micro-AB
>> receptacle and requires such dynamic role switching. So I kind of
> 
> I meant the real customer use cases, not the EVMs ;)
> 
I am using the about the second port on am335x evm which is used as
host (not OTG mode (3) but HOST (1)). If I start the timer OTG after
disconnect I see that it gets back to A mode:

[   97.570852] musb-hdrc musb-hdrc.1.auto: Poll devctl 19 (a_wait_bcon)
[   99.570306] musb-hdrc musb-hdrc.1.auto: Poll devctl 98 (a_idle)
…
[  209.570259] musb-hdrc musb-hdrc.1.auto: Poll devctl 80 (a_idle)

and now the session bit is missing and never gets back so I can not
plug any other device. I really have no idea what is missing here…

Sebastian
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