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Date: Wed, 2 Jan 2008 09:17:28 -0800
From: David Brown <mtd@davidb.org>
To: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Subject: Re: Does UBI support MLC nand flash?
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Cc: Nancy <nancydreaming@gmail.com>, kmpark@infradead.org,
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On Wed, Jan 02, 2008 at 11:13:00AM -0600, Josh Boyer wrote:
>On Wed, 2 Jan 2008 08:52:28 -0800
>David Brown <davidb@davidb.org> wrote:
>
>> On Wed, Jan 02, 2008 at 06:39:45AM -0600, Josh Boyer wrote:
>> >On Wed, 2 Jan 2008 14:19:16 +0800
>> >Nancy <nancydreaming@gmail.com> wrote:
>> >
>> >> oh, forgot to metion UBI.
>> >> UBI has two headers for each LED/PED, they are not write at same time.
>> >> Is that against MLC nand's no ramdom write and  write only once
>> >> permission?
>> >
>> >Not to my knowledge.  The second header is written to the second page
>> >in the block if subpage writes aren't supported by the underlying
>> >chip.  That should still work fine for MLC.
>> 
>> Many MLC devices will not allow you to write to the second page after
>> having written to the third or subsequent pages.  Would this still work?
>
>Yes... UBI doesn't write actual data to the blocks until both headers
>are in place.

I guess I need to read up more.  I though the second header was written
after the data had been written.  In that case, it would probably be fine.

Dave