RE: [EXT] Re: [RESEND PATCH V2 2/2] mtd: core: NAND filling block

["Bean Huo (beanhuo)" <beanhuo@xxxxxxxxxx>]

Hi, Boris

>
>On Mon, 21 Jan 2019 10:04:15 +0000
>"Bean Huo (beanhuo)" <beanhuo@xxxxxxxxxx> wrote:
>
>> Hi, Boris
>>
>> >On Fri, 18 Jan 2019 22:12:04 +0000
>> >"Bean Huo (beanhuo)" <beanhuo@xxxxxxxxxx> wrote:
>> >
>> >> +	/* Corrupt page0 and page1, in order to simulate an
>> >> +	 * uncompleted eraseing scenario. Just for case of
>> >> +	 * power loss hits while below programming. in this
>> >> +	 * way, the PEB will be re-erased again.
>> >> +	 */
>> >> +	empty_page_mask |= 0x3;
>> >> +	memset(data_buf, 0xAA,  mtd->writesize);
>> >
>> >Why do you use the 0xaa pattern BTW?
>>
>> Random pattern or any pattern is ok. Just to fill in page.
>
>Let's use 0x0 then. This way all cells are actually in a "programmed"
>state. 
The proposed solution is effective in addressing the problem. A 00h pattern would also
work but it would add unnecessary stress to the device, by programming more memory cells.

>BTW, I'd still be interested in knowing more about the root cause of this
>issue. What causes this wrong "cell is erased" detection in your chips? I thought
>the ERASE operation was an iterative process and cells were being tested after
>each step to know whether they are erased or not in order to decide to do
>another step or stop.
>Am I wrong? What happens here to cause this erroneous detection?

I cannot comment on the details of the detection procedure, which is proprietary algorithm. The patch ensures that the erase detection is accurate.

//Bean  

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