Re: [bug] kernel panic if writting data to mmc after suspendding

[Nguyen Viet Dung <nv-dung@jinso.co.jp>]

Hi Ulf

I want to test this problem withc your patch.
Please sent pacthset for me.
I have checked below link but detail of patch haven't.

Best regard,
Nguyen Viet Dung

On 2015年12月22日 12:16, Nguyen Viet Dung wrote:
> Hi Geert
>
> Thank for your reply.
>
> On 2015年12月18日 19:27, Ulf Hansson wrote:
>> On 18 December 2015 at 10:33, Geert Uytterhoeven 
>> <geert@linux-m68k.org> wrote:
>>> Hi Dung-san,
>>>
>>> CC Ulf
>>>
>>> On Mon, Dec 14, 2015 at 3:34 AM, Nguyen Viet Dung 
>>> <nv-dung@jinso.co.jp> wrote:
>>>> While is testting LTSI-v4.1.13-rc1, we have found the following the 
>>>> failure
>>>> of mmcif.
>>>> 1. mount mmc block
>>>> 2. write data to mmc block
>>>> 3. suspend/resume
>>>> 4. write data to mmc block one again => happen kernel panic
>>>> (Probability in this test procedure is 100%)
>>>>
>>>> We have used git bisect to find cause of failure in LTS-v4.1.13 to
>>>> LTSI-v4.1.13-rc1
>>>> and have found commit which cause failure.
>>>> (On LTS-v4.1.13 has not this failure)
>>>>   drivers: sh: Disable PM runtime for multi-platform ARM with genpd
>>>>   commit :cbc41d0a761bffb3166a413a3c77100a737c0cd7
>>> That means there's a bug in Runtime PM handling of the sh_mmcif 
>>> driver, or
>>> in the MMC subsystem.
>>>
>>> Usually such bugs cause a kernel hang on register access, not a NULL 
>>> pointer
>>> dereference, though.
>> Agree!
>>
>> I doubt the bisected commit is where the *real* issue is. Looking into
>> the details for how system PM and runtime PM is deployed in sh_mmcif,
>> I believe some improvements are needed.
>>
>> Actually, I made an attempt to modernize the PM code for sh_mmcif a 
>> while ago.
>> http://marc.info/?l=linux-mmc&m=138245085523815&w=2
>>
>> Whether that fixes the problem reported here, I have no idea. Although
>> if not, it should move the code to a position where it becomes easier
>> to properly fix this issue.
>>
>> I am willing to help and rebase that patchset, but I require help in
>> testing since I haven't been able to get a hold of a HW. Can I count
>> on that?
> Yes , I can help you test.
> If you have rebased patchset, phease tell me.
>
> Best regards,
> Nguyen Viet Dung