lkml.org 
[lkml]   [2017]   [Apr]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
Subjectfsl_ifc_nand: are blank pages protected by ECC?
Hi!

We have some problems with fsl_ifc_nand ... in the old kernels, but
this one does not seem to be fixed in v4.11, either.

UBIFS complains:

UBIFS error (pid 931): ubifs_scan: corrupt empty space at LEB 282:252630
UBIFS error (pid 931): ubifs_scanned_corruption: corruption at LEB 282:252630
UBIFS error (pid 931): ubifs_scanned_corruption: first 1322 bytes from LEB 282:252630
UBIFS error (pid 931): ubifs_scan: LEB 282 scanning failed

Possible explanation is here:

https://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/716/t/289605

# I see on the forum that this issue has been raised before - my
# understanding is that the omap2 nand driver does not perform ECC
# detection/correction on empty pages so when UBIFS checks the empty
# space data and doesn't read all 0xFF then it fails and mounts
# read-only. I didn't find any good solution - only a workaround to
# remove the UBIFS check..

So I checked fsl_ifc_nand.c in v4.11-rc, and yes, it seems to have the
same problem:

if (errors == 15) {
/*
* Uncorrectable error.
* OK only if the whole page is blank.
*
* We disable ECCER reporting due to...
* erratum IFC-A002770 -- so report it now if we
* see an uncorrectable error in ECCSTAT.
*/
if (!is_blank(mtd, bufnum))
ctrl->nand_stat |=
IFC_NAND_EVTER_STAT_ECCER;
break;
}

is_blank() checks for all 0xff's, so single-bit 0xfe in the data will
result in_blank() == 0 and uncorrectable error being signaled.

Should the driver be modified somehow?

Thanks,
Pavel

--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2017-04-19 14:14    [W:0.086 / U:10.192 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site