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

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

Hi Bin,

On 5/15/2014 8:49 PM, Bin Liu wrote:
> George,
>
> On Thu, May 15, 2014 at 1:28 AM, George Cherian <george.cherian@ti.com> wrote:
>> 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
> The test is done. The babble always causes STUCK_J is reset,
> MUSB_BABBLE_CTL is 0x44 or 0x4. MUSB reset happens.
Thankyou Bin for the help.

Can I get a Tested-by from you?
> Do you think when re-start happens the driver should print a message
> on console saying re-start due to babble? It would help debug the
> babble problems while the dynamic debug is off.

It prints  out a message saying babble condition occured.
More over, it re-enumerates all the devices connected  as part of Musb 
re-start.
Don't you think that is sufficient enough ?
> Thanks,
> -Bin.
>
>>> 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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>>>>>>> in
>>>>>>>
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>>>>>
>>>>>
>>>>> --
>>>>> -George
>>>>>
>>
>> --
>> -George
>>


-- 
-George