Re: How the bad blocks occured in despite MTD manages the bad blocks

[JH <jupiter.hce@xxxxxxxxx>]

Thanks Richard and Steve.

On 10/3/19, Richard Weinberger <richard.weinberger@xxxxxxxxx> wrote:
>> My understinding is that MTD manages the NAND bad blocks, but can the
>> MTD prevent bad blocks happening?
>
> It does not. UBI does by applying wear-leveling.

I should mention it is the rootfs using ubifs, the kernel is 5.1.

>> My iMX6 NAND device was only up and running about a month, it now
>> failed to boot from NAND due to the bad blocks:
>
> Why do you think so?

I was told by hardware engineer, it was broken by bad block problem.

>> (a) what could be common cause to trigger bad blacks?
>
> Mostly due to block aging.

>> (b) if I reflush the NAND will the bad blacks recovered or just mapped
>> it to bad block list?
>
> A bad block will be bad forever.
>
>> .......
>> Bad block table found at page 131008, version 0x01
>> Bad block table found at page 130944, version 0x01
>
> Having a bad block table is nothing bad.

So that was not the cause to break the boot.

>> ................
>> [FAILED] Failed to mount Kernel Debug File System.
>> [FAILED] Failed to mount Temporary Directory (/tmp).
>> [FAILED] Failed to start Remount Root and Kernel File Systems.
>> [FAILED] Failed to mount /var/volatile.
>> [FAILED] Failed to mount FUSE Control File System.
>
> This lines are useless. Why exactly is it failing? And *what* fails?

After those lines, the boot stopped in an emergent mode in a prompt to
suggest to log in by Ctl-D, but that could not work, I was not able to
log into the file system, nor can I get kernel log. From your
experience, what could be likely the causes, hardware or software?

Thanks Steve and Richard.

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/