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Date: Thu, 31 Oct 2013 12:32:43 -0300
From: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
To: Brian Norris <computersforpeace@gmail.com>
Subject: Re: [PATCH] mtd: nand_bbt: kill NAND_BBT_SCANALLPAGES
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On Thu, Oct 31, 2013 at 11:22:45AM -0400, Brian Norris wrote:
> On Thu, Oct 31, 2013 at 07:20:39AM -0300, Ezequiel Garcia wrote:
> > On Wed, Oct 30, 2013 at 10:29:35PM -0400, Brian Norris wrote:
> > > Now that the last user of NAND_BBT_SCANALLPAGES has been removed, let's
> > > kill this peculiar BBT feature flag.
> > > 
> > 
> > I must admit I also find this option a bit puzzling.
> > 
> > However, I'm wondering what happens if a manufacturer specifies
> > the bad block mark is in some page at the middle of a block.
> > 
> > AFAIK, some of them do exactly that, and I've always thought
> > this option was the solution for such cases.
> 
> Well, it's not really a *good* solution for a marker in the middle of
> the page, as it's both inaccurate and heavily inefficient.

Granted.

> I've never heard of such a device. (There is a rare one or two that uses
> the 2nd-to-last or 3rd-to-last page.) Do you have any examples?
> 

Not at hand.

> > So, is this really no longer needed?
> 
> I think it just adds unnecessary complexity to nand_bbt.c. Generally,
> the fewer (unused) options the better. Also, this helps clear the way
> for some nand_base/nand_bbt simplification that I have planned.
> 
> Additionally, I think its only users were either accidental (in the case
> of omap2.c) or lazy (which didn't want to figure out the correct pages
> to scan for bad block markers). And now there are no users.
> 

Ok, agreed. But do we have any mechanism to scan a *particular*
page?

-- 
Ezequiel García, Free Electrons
Embedded Linux, Kernel and Android Engineering
http://free-electrons.com