[U-Boot] [PATCHv1 02/22] arm: socfpga: enable saveenv to mmc partition

[Marek Vasut]

On Friday, January 16, 2015 at 05:50:18 AM, Stefan Roese wrote:

Hi!

> >> Would it make sense to make environment bigger (64K?) at this point,
> >> and enabling the redundant environment option, so that one bad block
> >> does not bring the whole device down?
> > 
> > Do you think you'll ever have more than a 4KiB of text data in the env ?
> 
> I have used bigger environment in some cases.
> 
> > I can see a reason for some 16 KiB environment, but that's the ceiling.
> 
> Then lets switch to at least 8KiB please.
> 
> Pavel, would be 8KiB enough for your project?
> 
> > Usually, the env only has to be a few KiB and it's size has to be
> > multiple of the underlying device's erase block. But in case of SD card,
> > there are no explicit erase blocks exported to the user, all is hidden
> > by the controller in the SD card and gives an illusion of a device which
> > has 512b blocks and the user doesn't care for bad block management.
> > Since the controller in the card does the bad block management and wear
> > leveling/relocation of blocks, it also means that in case the controller
> > did fail to provide the block which contains env, the whole card would
> > already be in a very bad state.
> 
> Right. Nevertheless it makes sense to support the redundant envrionment
> (at least from my point of view), regardless of the device the
> evironment is stored in. Thinking for example about power-supply failure
> (power-cut) while writing into the one envrionment version.

That's a fine idea, you're right :)

Best regards,
Marek Vasut