Re: [PATCH v2] mmc: Resolve BKOPS compatability issue

[Jaehoon Chung <jh80.chung@samsung.com>]

Hi,

On 01/30/2015 07:25 PM, Ulf Hansson wrote:
> On 30 January 2015 at 08:26, Jaehoon Chung <jh80.chung@samsung.com> wrote:
>> Hi, Alexey.
>>
>> On 01/29/2015 05:49 PM, Alexey Skidanov wrote:
>>> This patch is coming to fix compatibility issue of BKOPS_EN  field of EXT_CSD.
>>> In eMMC-5.1, BKOPS_EN was changed, and now it has two operational bits:
>>> Bit 0 - MANUAL_EN
>>> Bit 1 - AUTO_EN
>>> In previous eMMC revisions, only Bit 0 was supported.
>>
>> If "manual enable" is the same functionality with previous enable,
>> I think it doesn't need to change the name..
>> Just checking whether enable or not with Mask bit?
>>
>> If need to add the auto enable, only add the bkops_auto_en in future.
>> This is just my preference..and i don't read the spec since i don't have eMMC5.1 spec.
>>
>> If manual-enable is difference with previous enable, how about using bkops-manual-en?
> 
> According to information I have got around the eMMC 5.1 spec, the old
> value of MAN_EN will remain. That also means that bit will remain as
> one time programmable.
> 
> The new AUTO_EN bit, will be multiple writeable with value kept after
> power failure. But more importantly, the card seems to expect the host
> to disable AUTO_EN before power failure. In other words we need to
> disable AUTO_EN (if set) before entering system PM state an cutting
> power to the card.

Thanks for information.. I want to get this information,
I think auto_en bit can be used usefully.

Best Regards,
Jaehoon Chung

> 
> So, yes, we will have to deal with AUTO_EN sooner or later, thus I am
> kind of happy Alexey's patch, as is.
> 
> Kind regards
> Uffe
>