Re: mtd-utils io_paral test fails on NAND

[Richard Weinberger <richard@xxxxxx>]

Otto,

----- Ursprüngliche Mail -----
> Von: "Otto Blom" <oblom586@xxxxxxxxx>
> An: "richard" <richard@xxxxxx>
> CC: "linux-mtd" <linux-mtd@xxxxxxxxxxxxxxxxxxx>
> Gesendet: Dienstag, 26. November 2019 18:11:09
> Betreff: Re: mtd-utils io_paral test fails on NAND

> Hi Richard !
> 
> nandpagetest ran for 12h+ w/o failing, so it looks like a driver
> problem like you suggested.
> 
> All the times I've seen if fail (around 10) the failed page came back
> with all zeros.. Which is a bit strange as I would think "random" /
> duplicated page would be more likely. Maybe the page read fails
> silently and the controller returns all zeros

If I was in your situation I'd try to figure where the 0x00 bytes come from.
Does the driver write zeros? Maybe the page is zero initialized and the controller
completely fails to transfer data and does not signal it?

Since nandpagetest works, but UBI not it points into the direction of DMA.
On the other hand, UBI uses offsets. Maybe this is broken in the driver...

I had more than once the case where a driver worked like charm if you asked
it for a single page or a whole block but failed if you asked for N pages
at a given offset.

Thanks,
//richard

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