Re: [PATCH v5] MMC-4.5 Power OFF Notify Rework

On 06/15/2012 01:34 PM, Saugata Das wrote:
> On 15 June 2012 16:56, Ulf Hansson<ulf.hansson <at> stericsson.com>  wrote:
>> Hi Saugata,
>>
>> snip.
>>
>>
>>>>>>>
>>>>>>> The problem in sending CMD0 without power OFF notify is possibility of
>>>>>>> some data loss in MMC-4.5 devices.
>>>>>>
>>>>>>
>>>>>>
>>>>>> I don't see the problem here. You will be sending power OFF notify when
>>>>>> you
>>>>>> can. The only difference is when you "wake" the device from sleep mode.
>>>>>> Instead of using CMD5, which may work is some cases and in some cases
>>>>>> not
>>>>>> (without restoring ios). So using CMD0 as common way of waking up from
>>>>>> suspend should be fine. Unless I missed something of course. 
>>>>>>
>>>>>
>>>>> CMD0 is a reset. I expect with power OFF notify enable, the eMMC
>>>>> device will postpone some control information update to its internal
>>>>> non-volatile memory (e.g. some data structures which are kept in the
>>>>> controller buffers and not stored in NAND). If we do a CMD0, then the
>>>>> eMMC device will be reset and we may lose some data. In addition to
>>>>> that, doing complete card initialization will increase the wakeup time
>>>>> (for 4.4 devices).
>>