Subject: Re: [PATCH] powerpc/config: Disable the 4KiB erase granularity of SPI flash

From: Scott Wood <[email-masked]>
Date: Wed, 06 Apr 2016 17:01:29 -0500

On Wed, 2016-04-06 at 18:14 +0800, Zhiqiang Hou wrote:
> From: Hou Zhiqiang <[email-masked]>
> 
> Disable the subsector (4KiB) erase granularity to speed up the erase
> operation.
> 
> Signed-off-by: Hou Zhiqiang <[email-masked]>
> ---
>  arch/powerpc/configs/85xx-hw.config | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/powerpc/configs/85xx-hw.config b/arch/powerpc/configs/85xx
> -hw.config
> index 528ff0e..a0f4e70 100644
> --- a/arch/powerpc/configs/85xx-hw.config
> +++ b/arch/powerpc/configs/85xx-hw.config
> @@ -77,6 +77,7 @@ CONFIG_MTD_PHYSMAP_OF=y
>  CONFIG_MTD_PHYSMAP=y
>  CONFIG_MTD_PLATRAM=y
>  CONFIG_MTD_SPI_NOR=y
> +# CONFIG_MTD_SPI_NOR_USE_4K_SECTORS is not set
>  CONFIG_NETDEVICES=y
>  CONFIG_NVRAM=y
>  CONFIG_PATA_ALI=y

Is there a reason specific to 85xx to have a different default than every
other platform except lpc18xx?  The description of MTD_SPI_NOR_USE_4K_SECTORS
acknowledges that erase speed is a tradeoff.  Why is that concern more
compelling on 85xx than elsewhere?

-Scott