Re: [PATCH v3 0/5] Add support for SW babble Control

[George Cherian <george.cherian@ti.com>]

Hi Bin,

On 5/14/2014 10:13 PM, Bin Liu wrote:
> George,
>
> On Wed, May 14, 2014 at 9:34 AM, Bin Liu <binmlist@gmail.com> wrote:
>> George,
>>
>> On Wed, May 14, 2014 at 12:37 AM, George Cherian <george.cherian@ti.com> wrote:
>>> On 5/14/2014 12:07 AM, Bin Liu wrote:
>>>> Hi,
>>>>
>>>> On Tue, May 13, 2014 at 8:24 AM, George Cherian <george.cherian@ti.com>
>>>> wrote:
>>>>> Hi Daniel,
>>>>>
>>>>>
>>>>> On 5/13/2014 6:44 PM, Daniel Mack wrote:
>>>>>> Hi George,
>>>>>>
>>>>>> On 05/13/2014 02:57 PM, George Cherian wrote:
>>>>>>> I never enabled the MUSB_BABBLE_SW_SESSION_CTRL in the MUSB_BABBLE_CTL
>>>>>>> reg.
>>>>>>> can you try with the following patch.
>>>>>>>
>>>>>>> diff --git a/drivers/usb/musb/musb_dsps.c
>>>>>>> b/drivers/usb/musb/musb_dsps.c
>>>>>>> index 1ae6681..1160cd1 100644
>>>>>>> --- a/drivers/usb/musb/musb_dsps.c
>>>>>>> +++ b/drivers/usb/musb/musb_dsps.c
>>>>>>> @@ -477,8 +477,11 @@ static int dsps_musb_init(struct musb *musb)
>>>>>>>            * logic enabled.
>>>>>>>            */
>>>>>>>           val = dsps_readb(musb->mregs, MUSB_BABBLE_CTL);
>>>>>>> -       if (val == MUSB_BABBLE_RCV_DISABLE)
>>>>>>> +       if (val == MUSB_BABBLE_RCV_DISABLE) {
>>>>>>>                   glue->sw_babble_enabled = true;
>>>>>>> +               val |= MUSB_BABBLE_SW_SESSION_CTRL;
>>>>>>> +               dsps_writeb(musb->mregs, MUSB_BABBLE_CTL, val);
>>>>>>> +       }
>>>>>>>           ret = dsps_musb_dbg_init(musb, glue);
>>>>>>>           if (ret)
>>>>>> MUSB_BABBLE_STUCK_J still remains unset, so I get the same result as
>>>>>> without the patch: a full glue reset is conducted. Do I get you right
>>>>>> that you expect MUSB_BABBLE_STUCK_J to be set in babble conditions when
>>>>>> MUSB_BABBLE_SW_SESSION_CTRL is set?
>>>>>>
>>>>> Basically, there are 2 types of babble conditions.
>>>>> 1) Transient babble condition - which could be recovered from without an
>>>>> IP
>>>>> reset .
>>>>> 2) Babble condition - which could be recovered from only by doing an IP
>>>>> reset.
>>>>>
>>>>> Looks like you are always hitting case 2 (Most times am also hitting the
>>>>> same).
>>>>> Case 1 is really hard to reproduce. I don't have a reliable method as of
>>>>> now
>>>>> to
>>>>> reproduce this case consistently.
>>>>>
>>>>>> [   19.672373] CAUTION: musb: Babble Interrupt Occurred
>>>>>> [   19.677776] musb_stage0_irq 789: unhandled DISCONNECT transition
>>>>>> (a_wait_bcon)
>>>>>> [   19.685815] usb 1-1: USB disconnect, device number 3
>>>>>> [   19.769720] musb-hdrc musb-hdrc.0.auto: babble: MUSB_BABBLE_CTL value
>>>>>> 44
>>>>>> [   19.776765] musb-hdrc musb-hdrc.0.auto: STUCK_J is reset
>>>>>>
>>>>>>
>>>>>> I don't quite follow, especially as I lack documentation of the IP core.
>>>>>> How do you test babble errors, is there any way to force them to happen
>>>>>> reliably?
>>>>>
>>>>> There is no 100% reliable method to force it to happen. Following is
>>>> I have a way to force babble happen reliably - shorting DP or DM to
>>>> VBUS. I opened the far-end plug of the USB cable, so I can easily
>>>> short DP or DM to VBUS.
>>> Good to know that you have a reliable way to test babble condition.
>>> Can you please do a quick test on 3.15.0-rc4 with the series applied?
>>> In case of any assistance please do let me know.
>> Sure, but could you please re-send those patches to my corporate email
>> so that I can apply them from Thunderbird?
> You don't have to resend the patches. Nishanth Menon showed me a way
> to extract the patch from Gmail - Thanks Nishanth.
>
> But which repo do you want to me test with? The first patch ([PATCH v2
> 1/5] usb: musb: core: Convert babble recover work to delayed work)
> does not apply to v3.15-rc4 tag. the current musb_core.c does not have
> the recovery work for musb. Please let me know what I missed.
Oops I missed to mention the same.
Please try on
git://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb.git master
> Thanks,
> -Bin.
>
>> I read these linux-usb emails in Gmail, and  am not aware of any easy
>> way to extract patches from Gmail.
>>
>> BTY, I tested with TI 3.12.10 kernel, in which I guess the babble
>> handling is similar to this patch set. With TI3.12.10, MISC is always
>> 0x64, so MUSB never restarts.
>>
>> Thanks,
>> -Bin.
>>
>>>> But the interesting thing is that with TI 3.2 kernel, shorting DP or
>>>> DM to VBUS causes MISC register to be 0x4, but the result is
>>>> completely opposite in TI 3.12.10 kernel, which cause MISC to be 0x64.
>>>>
>>>> So in the 3.2 kernel, the babble handing resets the controller, but
>>>> the 3.12.10 does not.
>>>>
>>>> Regards,
>>>> -Bin.
>>>>
>>>>> my setup ,
>>>>> I have a HUB with 4 devices connected , which gives me a Babble interrupt
>>>>> on both connects and disconnects ( Not always though).
>>>>>
>>>>>> Anyway, the full glue layer solves this rare condition quite well for
>>>>>> me. Is there any downside of this?
>>>>>>
>>>>>>
>>>>>> Daniel
>>>>>>
>>>>> --
>>>>> -George
>>>>>
>>>>> --
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>>>
>>>
>>> --
>>> -George
>>>


-- 
-George