Re: [PATCH v10 2/5] mtd: nand: vf610_nfc: add hardware BCH-ECC support

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 




On 26 Aug 2015, computersforpeace@xxxxxxxxx wrote:

> On Wed, Aug 26, 2015 at 10:57:38AM -0700, Stefan Agner wrote:
>> When printing the ECC error count on ECC fail when reading an erased
>> NAND flash, the numbers of bit flips (stuck at zero) seem to widely
>> correlate with the number returned by the controller. While it seems
>> to correlate widely, there are exceptions, as discussed in the
>> thread: http://thread.gmane.org/gmane.linux.ports.arm.kernel/295424

>> Maybe this is an artifact of the ECC algorithm we just
>> can't/shouldn't rely on? I am not sure where this originated, I did
>> not found any indication in the reference manual about what that
>> value contains in the error case.

> Doesn't sound too reliable to me. And I'm not sure even if it was
> reliable, that it would provide much value. We have to a lot of
> re-counting anyway, so we might as well just be using our own
> threshold.  Or maybe I'm missing the point.

>> Bill, do you have an idea why we used that value as threshold in
>> early implementations?

>> Otherwise I also think we should just drop the use of this value.

Yes, using this value is not especially useful if we re-read with ECC
disabled to count the bit flips for erased pages.   I think this is what
Stefan has done in the 11th patch set.

-- 
Married men live  longer than single men, but married  men are much more
willing to die - Dilworth
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Device Tree Compilter]     [Device Tree Spec]     [Linux Driver Backports]     [Video for Linux]     [Linux USB Devel]     [Linux PCI Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Yosemite Backpacking]
  Powered by Linux