Re: mmc: dw_mmc: log spamming

[Tobias Jakobi <tjakobi@math.uni-bielefeld.de>]

Hello Jaehoon,


Jaehoon Chung wrote:
> Hi Tobias,
> 
> CC'd mmc mailing.
> 
> On 09/19/2016 10:03 AM, Seung-Woo Kim wrote:
>> Hello Jaehoon,
>>
>> On 2016년 09월 19일 09:32, Jaehoon Chung wrote:
>>> Hi Tobias,
>>>
>>> On 09/16/2016 02:29 AM, Tobias Jakobi wrote:
>>>> Hello everyone,
>>>>
>>>> I'm experiencing massive kernel log spamming by dw_mmc, the commit that
>>>> causes this is the following one.
>>>>
>>>> 65257a0deed5aee66b4e3708944f0be62a64cabc
>>>>
>>>> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=65257a0deed5aee66b4e3708944f0be62a64cabc
>>>>
>>>> I've briefly checked the commit and I think the rationale behind
>>>> removing the check is incorrect. While MMC_CLKGATE was certainly
>>>> removed, runtime PM has "replaced" it (the commit
>>>> 9eadcc0581a8ccaf4c2378aa1c193fb164304f1d even mentions this).
>>>>
>>>> This is on an Exynos4412 board, kernel is 4.8-rc6. Nothing is connected
>>>> to the eMMC connector.
>>>
>>> Thanks for reporting this.
>>>
>>> Seung-Woo, Could you check your patch? I will also check this.
> 
> Did you test after reverting this commit? or previous version is working fine?
yes, reverting the commit fixes the log spamming. I'm aware though that
the check is more of less broken (undefined behaviour because of
bit-shifting with large values), so I have also tried the following
thing: Just checking against 'div' instead of 'clock << div'. Anyway,
this also works for me.


> Which exynos4412 board do you use? I think it's related with "broken-cd".
> (If you can share which board and dts you are using, we can check in more detail.)
This is an Odroid-X2 board.


> As you mentioned, you didn't insert the eMMC card on board.
> Then it should be polling whether card is inserted/removed. (If broken-cd is set...)
I can check the callstack leading to dw_mci_setup_bus() I guess. Would
that should make it easier for you guys to understand where the issue
originates from?


> I think it's not related with runtime PM.
> 
> Best Regards,
> Jaehoon Chung

WIth best wishes,
Tobias




>> Ok, I will check on Exynos4412 SpC boards.
>>
>> By the way, to check no condition case, when I posted after v2[1], I
>> checked with Exynos5422 and Exynos5433 SoC boards and they didn't show
>> duplicated log, so I agreed not to check condition for logging.
>>
>> [1] https://patchwork.kernel.org/patch/9182469/
>>
>> Best Regards,
>> - Seung-Woo Kim
>>
>>>
>>> Best Regards,
>>> Jaehoon Chung
>>>
>>>>
>>>> With best wishes,
>>>> Tobias
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>
>