On Wed, 22 Mar 2017 23:07:17 +0900 Masahiro Yamada <[email protected]> wrote: > dev_err(denali->dev, > @@ -1148,12 +1136,15 @@ static int denali_read_page(struct mtd_info *mtd, > struct nand_chip *chip, > if (check_erased_page) { > read_oob_data(mtd, chip->oob_poi, denali->page); > > - /* check ECC failures that may have occurred on erased pages */ > - if (check_erased_page) { > - if (!is_erased(buf, mtd->writesize)) > - mtd->ecc_stats.failed++; > - if (!is_erased(buf, mtd->oobsize)) > - mtd->ecc_stats.failed++; > + stat = nand_check_erased_ecc_chunk( > + buf, mtd->writesize, > + chip->oob_poi, mtd->oobsize, > + NULL, 0, > + chip->ecc.strength * chip->ecc.steps);
That's not how it's supposed to be done. Each chunk should be checked independently. Here is a simple example explaining why this is important: Let's consider the following setup: - 4k pages - 16bits/1024bytes ECC With your approach, you turn this into: - 4k pages - 64bits/4096bytes ECC Now suppose you have 32 bitflips in the first 1024 bytes. The real ECC config is expected to report uncorrectable errors, but your approach will just report that 32 bits have been fixed, which is wrong.
