On 12/3/18 1:02 PM, Richard Weinberger wrote:
Am Montag, 3. Dezember 2018, 19:55:46 CET schrieb Piotr Wojtaszczyk:
On Thu, 29 Nov 2018 22:12:50 +0100 (CET)
Thomas Gleixner <tglx at linutronix.de> wrote:
> On some Micron NAND chips block erase fails occasionaly despite the chip
> claiming that it succeeded. The flash block seems to be not completely
> erased and subsequent usage of the block results in hard to decode
and very
> subtle failures or corruption.
Doesn't UBI check block after erase in do_sync_erase()? Do the bitflips
develop over time?
You mean ubi_self_check_all_ff()? This is a very expensive self-check
which is disabled by default and makes only sense then you test UBI itself.
Also think of power-cuts, what happens if you face power-loss right
after mtd_erase() and before the check?
Finally, I'm not sure if you can detect partial erase right after
mtd_erase(). I fear failure happens after you write to that block.
Thanks,
//richard
Oh yes the ubi_self_check_all_ff() is indeed disabled. Partially erased
blocks I think are being caught at attach in scan_peb(), they are put in
ai->erase list for later erase again.
--
Peter
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