Warning dump on OMAP-L138 when g_zero module is removed

[nsekhar@ti.com (Sekhar Nori)]

On Thursday 06 July 2017 10:43 PM, Alexandre Bailon wrote:
> On 06/29/2017 03:50 PM, Sekhar Nori wrote:
>> Hi Alexandre, Bin,
>>
>> With latest linux-next, I see a warning dump when I remove g_zero[1] on 
>> OMAP-L138 LCDK board. I am building the kernel with davinci_all_defconfig.
>>
>> It is not present in latest mainline because the warnings are introduced
>> with CPPI DMA getting enabled in latest -next.
>>
>> Subsequent insertion of g_ether leads to a warning too[2], although the 
>> gadget seems to work (ping test).
>>
>> Since these are pretty annoying, it will be nice to get rid of them. I 
>> have not been able to debug any further. But if you have
>> ideas/experiments to try, I can do that.

> I got a lot of these warnings during development but it was only for the
> host mode.
> If I remember correctly, the cause was a race between the teardown
> function and the interrupt handler.
> The teardwon descriptor was pop from the queue by the interrupt handler,
> preventing cppi41_tear_down_chan() to get it, which will result after
> some retries to a couple of warnings.
> 
> I will take a look to see if that is the same issue.

Thanks! I also see similar warnings under fast ping traffic and g_ether
inserted on LCDK. They dont come immediately though. Only after an hour
or so under traffic.

I can those provide logs too if its going to be helpful.

Thanks,
Sekhar