[PATCH next 2/2] spi: spi-qpic-snand: add support for 8 bits ECC strength

Mon May 12 01:32:23 PDT 2025

On 05/05/2025 at 15:21:52 +02, Gabor Juhos <j4g8y7 at gmail.com> wrote:

> 2025. 05. 05. 13:17 keltezéssel, Md Sadre Alam írta:
>> 
>> 
>
> [...]
>
>>>    [ 2720.344163] mtd_stresstest: 8192 operations done
>>>    [ 2761.645640] mtd_stresstest: 9216 operations done
>>>    [ 2791.760534] mtd_stresstest: finished, 10000 operations done
>>>    [ 2791.760817] =================================================
>>>    #
>> Could you please run biterror test "mtd_nandbiterrs" with the same device, since
>> you are adding 8-bit ECC support.
>
> Sure, here is the result:
>
> # insmod mtd_test
> # for i in $(seq 0 4); do insmod mtd_nandbiterrs; done
> [   45.405610]
> [   45.405638] ==================================================
> [   45.406164] mtd_nandbiterrs: MTD device: 0
> [   45.411807] mtd_nandbiterrs: MTD device size 268435456, eraseblock=131072,
> page=2048, oob=128
> [   45.415990] mtd_nandbiterrs: Device uses 1 subpages of 2048 bytes
> [   45.424495] mtd_nandbiterrs: Using page=0, offset=0, eraseblock=0
> [   45.434686] mtd_nandbiterrs: incremental biterrors test
> [   45.436653] mtd_nandbiterrs: write_page
> [   45.442634] mtd_nandbiterrs: rewrite page
> [   45.446408] mtd_nandbiterrs: read_page
> [   45.450346] mtd_nandbiterrs: verify_page
> [   45.453320] mtd_nandbiterrs: Successfully corrected 0 bit errors per subpage
> [   45.457405] mtd_nandbiterrs: Inserted biterror @ 0/5
> [   45.464431] mtd_nandbiterrs: rewrite page
> [   45.470216] mtd_nandbiterrs: read_page
> [   45.473852] mtd_nandbiterrs: Read reported 1 corrected bit errors
> [   45.476909] mtd_nandbiterrs: verify_page
> [   45.483090] mtd_nandbiterrs: Successfully corrected 1 bit errors per subpage
> [   45.487098] mtd_nandbiterrs: Inserted biterror @ 0/2
> [   45.494111] mtd_nandbiterrs: rewrite page
> [   45.499850] mtd_nandbiterrs: read_page
> [   45.503557] mtd_nandbiterrs: Read reported 1 corrected bit errors
> [   45.506597] mtd_nandbiterrs: verify_page
> [   45.512777] mtd_nandbiterrs: Successfully corrected 2 bit errors per subpage
> [   45.516768] mtd_nandbiterrs: Inserted biterror @ 0/0
> [   45.523810] mtd_nandbiterrs: rewrite page
> [   45.529586] mtd_nandbiterrs: read_page
> [   45.533224] mtd_nandbiterrs: Read reported 1 corrected bit errors
> [   45.536305] mtd_nandbiterrs: verify_page
> [   45.542464] mtd_nandbiterrs: Successfully corrected 3 bit errors per subpage
> [   45.546457] mtd_nandbiterrs: Inserted biterror @ 1/7
> [   45.553470] mtd_nandbiterrs: rewrite page
> [   45.559244] mtd_nandbiterrs: read_page
> [   45.562914] mtd_nandbiterrs: Read reported 2 corrected bit errors
> [   45.565991] mtd_nandbiterrs: verify_page
> [   45.572153] mtd_nandbiterrs: Successfully corrected 4 bit errors per subpage
> [   45.576142] mtd_nandbiterrs: Inserted biterror @ 1/5
> [   45.583158] mtd_nandbiterrs: rewrite page
> [   45.588927] mtd_nandbiterrs: read_page
> [   45.592599] mtd_nandbiterrs: Read reported 2 corrected bit errors
> [   45.595680] mtd_nandbiterrs: verify_page
> [   45.601840] mtd_nandbiterrs: Successfully corrected 5 bit errors per subpage
> [   45.605831] mtd_nandbiterrs: Inserted biterror @ 1/2
> [   45.612846] mtd_nandbiterrs: rewrite page
> [   45.618618] mtd_nandbiterrs: read_page
> [   45.622286] mtd_nandbiterrs: Read reported 2 corrected bit errors
> [   45.625434] mtd_nandbiterrs: verify_page
> [   45.631528] mtd_nandbiterrs: Successfully corrected 6 bit errors per subpage
> [   45.635517] mtd_nandbiterrs: Inserted biterror @ 1/0
> [   45.642533] mtd_nandbiterrs: rewrite page
> [   45.648303] mtd_nandbiterrs: read_page
> [   45.651975] mtd_nandbiterrs: Read reported 2 corrected bit errors
> [   45.655055] mtd_nandbiterrs: verify_page
> [   45.661215] mtd_nandbiterrs: Successfully corrected 7 bit errors per subpage
> [   45.665207] mtd_nandbiterrs: Inserted biterror @ 2/6
> [   45.672221] mtd_nandbiterrs: rewrite page
> [   45.677987] mtd_nandbiterrs: read_page
> [   45.681663] mtd_nandbiterrs: Read reported 3 corrected bit errors
> [   45.684741] mtd_nandbiterrs: verify_page
> [   45.690902] mtd_nandbiterrs: Successfully corrected 8 bit errors per subpage
> [   45.694892] mtd_nandbiterrs: Inserted biterror @ 2/5
> [   45.701908] mtd_nandbiterrs: rewrite page
> [   45.707678] mtd_nandbiterrs: read_page
> [   45.711351] mtd_nandbiterrs: error: read failed at 0x0
> [   45.714431] mtd_nandbiterrs: After 9 biterrors per subpage, read reported
> error -74
> [   45.722975] mtd_nandbiterrs: finished successfully.
> [   45.727101] ==================================================
> [   46.200485]
> [   46.200512] ==================================================
> [   46.201039] mtd_nandbiterrs: MTD device: 0
> [   46.206751] mtd_nandbiterrs: MTD device size 268435456, eraseblock=131072,
> page=2048, oob=128
> [   46.210763] mtd_nandbiterrs: Device uses 1 subpages of 2048 bytes
> [   46.219377] mtd_nandbiterrs: Using page=0, offset=0, eraseblock=0
> [   46.228941] mtd_nandbiterrs: incremental biterrors test
> [   46.231522] mtd_nandbiterrs: write_page
> [   46.237524] mtd_nandbiterrs: rewrite page
> [   46.241199] mtd_nandbiterrs: read_page
> [   46.245175] mtd_nandbiterrs: verify_page
> [   46.248195] mtd_nandbiterrs: Successfully corrected 0 bit errors per subpage
> [   46.252254] mtd_nandbiterrs: Inserted biterror @ 0/5
> [   46.259317] mtd_nandbiterrs: rewrite page
> [   46.265230] mtd_nandbiterrs: read_page
> [   46.268955] mtd_nandbiterrs: Read reported 1 corrected bit errors
> [   46.271784] mtd_nandbiterrs: verify_page
> [   46.277987] mtd_nandbiterrs: Successfully corrected 1 bit errors per subpage
> [   46.281941] mtd_nandbiterrs: Inserted biterror @ 0/2
> [   46.288985] mtd_nandbiterrs: rewrite page
> [   46.294803] mtd_nandbiterrs: read_page
> [   46.298414] mtd_nandbiterrs: Read reported 1 corrected bit errors
> [   46.301472] mtd_nandbiterrs: verify_page
> [   46.307677] mtd_nandbiterrs: Successfully corrected 2 bit errors per subpage
> [   46.311629] mtd_nandbiterrs: Inserted biterror @ 0/0
> [   46.318686] mtd_nandbiterrs: rewrite page
> [   46.324470] mtd_nandbiterrs: read_page
> [   46.328100] mtd_nandbiterrs: Read reported 1 corrected bit errors
> [   46.331159] mtd_nandbiterrs: verify_page
> [   46.337371] mtd_nandbiterrs: Successfully corrected 3 bit errors per subpage
> [   46.341316] mtd_nandbiterrs: Inserted biterror @ 1/7
> [   46.348365] mtd_nandbiterrs: rewrite page
> [   46.354123] mtd_nandbiterrs: read_page
> [   46.357787] mtd_nandbiterrs: Read reported 2 corrected bit errors
> [   46.360846] mtd_nandbiterrs: verify_page
> [   46.367047] mtd_nandbiterrs: Successfully corrected 4 bit errors per subpage
> [   46.371003] mtd_nandbiterrs: Inserted biterror @ 1/5
> [   46.378046] mtd_nandbiterrs: rewrite page
> [   46.383794] mtd_nandbiterrs: read_page
> [   46.387475] mtd_nandbiterrs: Read reported 2 corrected bit errors
> [   46.390534] mtd_nandbiterrs: verify_page
> [   46.396747] mtd_nandbiterrs: Successfully corrected 5 bit errors per subpage
> [   46.400691] mtd_nandbiterrs: Inserted biterror @ 1/2
> [   46.407733] mtd_nandbiterrs: rewrite page
> [   46.413483] mtd_nandbiterrs: read_page
> [   46.417190] mtd_nandbiterrs: Read reported 2 corrected bit errors
> [   46.420222] mtd_nandbiterrs: verify_page
> [   46.426419] mtd_nandbiterrs: Successfully corrected 6 bit errors per subpage
> [   46.430379] mtd_nandbiterrs: Inserted biterror @ 1/0
> [   46.437423] mtd_nandbiterrs: rewrite page
> [   46.443168] mtd_nandbiterrs: read_page
> [   46.446875] mtd_nandbiterrs: Read reported 2 corrected bit errors
> [   46.449908] mtd_nandbiterrs: verify_page
> [   46.456109] mtd_nandbiterrs: Successfully corrected 7 bit errors per subpage
> [   46.460066] mtd_nandbiterrs: Inserted biterror @ 2/6
> [   46.467109] mtd_nandbiterrs: rewrite page
> [   46.472888] mtd_nandbiterrs: read_page
> [   46.476569] mtd_nandbiterrs: Read reported 3 corrected bit errors
> [   46.479597] mtd_nandbiterrs: verify_page
> [   46.485796] mtd_nandbiterrs: Successfully corrected 8 bit errors per subpage
> [   46.489753] mtd_nandbiterrs: Inserted biterror @ 2/5
> [   46.496797] mtd_nandbiterrs: rewrite page
> [   46.502540] mtd_nandbiterrs: read_page
> [   46.506249] mtd_nandbiterrs: error: read failed at 0x0
> [   46.509284] mtd_nandbiterrs: After 9 biterrors per subpage, read reported
> error -74
> [   46.517867] mtd_nandbiterrs: finished successfully.
> [   46.521956] ==================================================
> [   47.150313]
> [   47.150341] ==================================================
> [   47.150867] mtd_nandbiterrs: MTD device: 0
> [   47.156564] mtd_nandbiterrs: MTD device size 268435456, eraseblock=131072,
> page=2048, oob=128
> [   47.160591] mtd_nandbiterrs: Device uses 1 subpages of 2048 bytes
> [   47.169201] mtd_nandbiterrs: Using page=0, offset=0, eraseblock=0
> [   47.178778] mtd_nandbiterrs: incremental biterrors test
> [   47.181350] mtd_nandbiterrs: write_page
> [   47.187334] mtd_nandbiterrs: rewrite page
> [   47.191016] mtd_nandbiterrs: read_page
> [   47.194997] mtd_nandbiterrs: verify_page
> [   47.198019] mtd_nandbiterrs: Successfully corrected 0 bit errors per subpage
> [   47.202081] mtd_nandbiterrs: Inserted biterror @ 0/5
> [   47.209132] mtd_nandbiterrs: rewrite page
> [   47.214962] mtd_nandbiterrs: read_page
> [   47.218554] mtd_nandbiterrs: Read reported 1 corrected bit errors
> [   47.221612] mtd_nandbiterrs: verify_page
> [   47.227814] mtd_nandbiterrs: Successfully corrected 1 bit errors per subpage
> [   47.231769] mtd_nandbiterrs: Inserted biterror @ 0/2
> [   47.238816] mtd_nandbiterrs: rewrite page
> [   47.244574] mtd_nandbiterrs: read_page
> [   47.248242] mtd_nandbiterrs: Read reported 1 corrected bit errors
> [   47.251300] mtd_nandbiterrs: verify_page
> [   47.257499] mtd_nandbiterrs: Successfully corrected 2 bit errors per subpage
> [   47.261457] mtd_nandbiterrs: Inserted biterror @ 0/0
> [   47.268504] mtd_nandbiterrs: rewrite page
> [   47.274301] mtd_nandbiterrs: read_page
> [   47.277930] mtd_nandbiterrs: Read reported 1 corrected bit errors
> [   47.280987] mtd_nandbiterrs: verify_page
> [   47.287187] mtd_nandbiterrs: Successfully corrected 3 bit errors per subpage
> [   47.291145] mtd_nandbiterrs: Inserted biterror @ 1/7
> [   47.298191] mtd_nandbiterrs: rewrite page
> [   47.303951] mtd_nandbiterrs: read_page
> [   47.307619] mtd_nandbiterrs: Read reported 2 corrected bit errors
> [   47.310675] mtd_nandbiterrs: verify_page
> [   47.316876] mtd_nandbiterrs: Successfully corrected 4 bit errors per subpage
> [   47.320832] mtd_nandbiterrs: Inserted biterror @ 1/5
> [   47.327875] mtd_nandbiterrs: rewrite page
> [   47.333629] mtd_nandbiterrs: read_page
> [   47.337305] mtd_nandbiterrs: Read reported 2 corrected bit errors
> [   47.340362] mtd_nandbiterrs: verify_page
> [   47.346563] mtd_nandbiterrs: Successfully corrected 5 bit errors per subpage
> [   47.350519] mtd_nandbiterrs: Inserted biterror @ 1/2
> [   47.357561] mtd_nandbiterrs: rewrite page
> [   47.363310] mtd_nandbiterrs: read_page
> [   47.367021] mtd_nandbiterrs: Read reported 2 corrected bit errors
> [   47.370050] mtd_nandbiterrs: verify_page
> [   47.376248] mtd_nandbiterrs: Successfully corrected 6 bit errors per subpage
> [   47.380207] mtd_nandbiterrs: Inserted biterror @ 1/0
> [   47.387250] mtd_nandbiterrs: rewrite page
> [   47.392996] mtd_nandbiterrs: read_page
> [   47.396703] mtd_nandbiterrs: Read reported 2 corrected bit errors
> [   47.399737] mtd_nandbiterrs: verify_page
> [   47.405936] mtd_nandbiterrs: Successfully corrected 7 bit errors per subpage
> [   47.409894] mtd_nandbiterrs: Inserted biterror @ 2/6
> [   47.416938] mtd_nandbiterrs: rewrite page
> [   47.422685] mtd_nandbiterrs: read_page
> [   47.426387] mtd_nandbiterrs: Read reported 3 corrected bit errors
> [   47.429424] mtd_nandbiterrs: verify_page
> [   47.435637] mtd_nandbiterrs: Successfully corrected 8 bit errors per subpage
> [   47.439582] mtd_nandbiterrs: Inserted biterror @ 2/5
> [   47.446624] mtd_nandbiterrs: rewrite page
> [   47.452369] mtd_nandbiterrs: read_page
> [   47.456080] mtd_nandbiterrs: error: read failed at 0x0
> [   47.459111] mtd_nandbiterrs: After 9 biterrors per subpage, read reported
> error -74
> [   47.467699] mtd_nandbiterrs: finished successfully.
> [   47.471784] ==================================================
> [   48.080311]
> [   48.080339] ==================================================
> [   48.080866] mtd_nandbiterrs: MTD device: 0
> [   48.086560] mtd_nandbiterrs: MTD device size 268435456, eraseblock=131072,
> page=2048, oob=128
> [   48.090590] mtd_nandbiterrs: Device uses 1 subpages of 2048 bytes
> [   48.099204] mtd_nandbiterrs: Using page=0, offset=0, eraseblock=0
> [   48.108765] mtd_nandbiterrs: incremental biterrors test
> [   48.111353] mtd_nandbiterrs: write_page
> [   48.117325] mtd_nandbiterrs: rewrite page
> [   48.121017] mtd_nandbiterrs: read_page
> [   48.124996] mtd_nandbiterrs: verify_page
> [   48.128017] mtd_nandbiterrs: Successfully corrected 0 bit errors per subpage
> [   48.132080] mtd_nandbiterrs: Inserted biterror @ 0/5
> [   48.139131] mtd_nandbiterrs: rewrite page
> [   48.144881] mtd_nandbiterrs: read_page
> [   48.148552] mtd_nandbiterrs: Read reported 1 corrected bit errors
> [   48.151611] mtd_nandbiterrs: verify_page
> [   48.157816] mtd_nandbiterrs: Successfully corrected 1 bit errors per subpage
> [   48.161768] mtd_nandbiterrs: Inserted biterror @ 0/2
> [   48.168891] mtd_nandbiterrs: rewrite page
> [   48.174571] mtd_nandbiterrs: read_page
> [   48.178241] mtd_nandbiterrs: Read reported 1 corrected bit errors
> [   48.181299] mtd_nandbiterrs: verify_page
> [   48.187500] mtd_nandbiterrs: Successfully corrected 2 bit errors per subpage
> [   48.191455] mtd_nandbiterrs: Inserted biterror @ 0/0
> [   48.198506] mtd_nandbiterrs: rewrite page
> [   48.204299] mtd_nandbiterrs: read_page
> [   48.207931] mtd_nandbiterrs: Read reported 1 corrected bit errors
> [   48.210985] mtd_nandbiterrs: verify_page
> [   48.217187] mtd_nandbiterrs: Successfully corrected 3 bit errors per subpage
> [   48.221142] mtd_nandbiterrs: Inserted biterror @ 1/7
> [   48.228188] mtd_nandbiterrs: rewrite page
> [   48.233950] mtd_nandbiterrs: read_page
> [   48.237617] mtd_nandbiterrs: Read reported 2 corrected bit errors
> [   48.240673] mtd_nandbiterrs: verify_page
> [   48.246872] mtd_nandbiterrs: Successfully corrected 4 bit errors per subpage
> [   48.250831] mtd_nandbiterrs: Inserted biterror @ 1/5
> [   48.257875] mtd_nandbiterrs: rewrite page
> [   48.263631] mtd_nandbiterrs: read_page
> [   48.267303] mtd_nandbiterrs: Read reported 2 corrected bit errors
> [   48.270361] mtd_nandbiterrs: verify_page
> [   48.276560] mtd_nandbiterrs: Successfully corrected 5 bit errors per subpage
> [   48.280531] mtd_nandbiterrs: Inserted biterror @ 1/2
> [   48.287592] mtd_nandbiterrs: rewrite page
> [   48.293338] mtd_nandbiterrs: read_page
> [   48.297030] mtd_nandbiterrs: Read reported 2 corrected bit errors
> [   48.300049] mtd_nandbiterrs: verify_page
> [   48.306247] mtd_nandbiterrs: Successfully corrected 6 bit errors per subpage
> [   48.310205] mtd_nandbiterrs: Inserted biterror @ 1/0
> [   48.317250] mtd_nandbiterrs: rewrite page
> [   48.322994] mtd_nandbiterrs: read_page
> [   48.326705] mtd_nandbiterrs: Read reported 2 corrected bit errors
> [   48.329736] mtd_nandbiterrs: verify_page
> [   48.335935] mtd_nandbiterrs: Successfully corrected 7 bit errors per subpage
> [   48.339892] mtd_nandbiterrs: Inserted biterror @ 2/6
> [   48.346936] mtd_nandbiterrs: rewrite page
> [   48.352633] mtd_nandbiterrs: read_page
> [   48.356391] mtd_nandbiterrs: Read reported 3 corrected bit errors
> [   48.359423] mtd_nandbiterrs: verify_page
> [   48.365626] mtd_nandbiterrs: Successfully corrected 8 bit errors per subpage
> [   48.369581] mtd_nandbiterrs: Inserted biterror @ 2/5
> [   48.376627] mtd_nandbiterrs: rewrite page
> [   48.382322] mtd_nandbiterrs: read_page
> [   48.386077] mtd_nandbiterrs: error: read failed at 0x0
> [   48.389110] mtd_nandbiterrs: After 9 biterrors per subpage, read reported
> error -74
> [   48.397695] mtd_nandbiterrs: finished successfully.
> [   48.401783] ==================================================
> [   48.940558]
> [   48.940586] ==================================================
> [   48.941112] mtd_nandbiterrs: MTD device: 0
> [   48.946811] mtd_nandbiterrs: MTD device size 268435456, eraseblock=131072,
> page=2048, oob=128
> [   48.950837] mtd_nandbiterrs: Device uses 1 subpages of 2048 bytes
> [   48.959448] mtd_nandbiterrs: Using page=0, offset=0, eraseblock=0
> [   48.969014] mtd_nandbiterrs: incremental biterrors test
> [   48.971596] mtd_nandbiterrs: write_page
> [   48.977594] mtd_nandbiterrs: rewrite page
> [   48.981277] mtd_nandbiterrs: read_page
> [   48.985247] mtd_nandbiterrs: verify_page
> [   48.988269] mtd_nandbiterrs: Successfully corrected 0 bit errors per subpage
> [   48.992327] mtd_nandbiterrs: Inserted biterror @ 0/5
> [   48.999428] mtd_nandbiterrs: rewrite page
> [   49.005508] mtd_nandbiterrs: read_page
> [   49.008836] mtd_nandbiterrs: Read reported 1 corrected bit errors
> [   49.011858] mtd_nandbiterrs: verify_page
> [   49.018061] mtd_nandbiterrs: Successfully corrected 1 bit errors per subpage
> [   49.022015] mtd_nandbiterrs: Inserted biterror @ 0/2
> [   49.029058] mtd_nandbiterrs: rewrite page
> [   49.034848] mtd_nandbiterrs: read_page
> [   49.038516] mtd_nandbiterrs: Read reported 1 corrected bit errors
> [   49.041545] mtd_nandbiterrs: verify_page
> [   49.047755] mtd_nandbiterrs: Successfully corrected 2 bit errors per subpage
> [   49.051702] mtd_nandbiterrs: Inserted biterror @ 0/0
> [   49.058760] mtd_nandbiterrs: rewrite page
> [   49.064565] mtd_nandbiterrs: read_page
> [   49.068203] mtd_nandbiterrs: Read reported 1 corrected bit errors
> [   49.071232] mtd_nandbiterrs: verify_page
> [   49.077432] mtd_nandbiterrs: Successfully corrected 3 bit errors per subpage
> [   49.081389] mtd_nandbiterrs: Inserted biterror @ 1/7
> [   49.088432] mtd_nandbiterrs: rewrite page
> [   49.094197] mtd_nandbiterrs: read_page
> [   49.097889] mtd_nandbiterrs: Read reported 2 corrected bit errors
> [   49.100919] mtd_nandbiterrs: verify_page
> [   49.107121] mtd_nandbiterrs: Successfully corrected 4 bit errors per subpage
> [   49.111077] mtd_nandbiterrs: Inserted biterror @ 1/5
> [   49.118137] mtd_nandbiterrs: rewrite page
> [   49.123892] mtd_nandbiterrs: read_page
> [   49.127576] mtd_nandbiterrs: Read reported 2 corrected bit errors
> [   49.130608] mtd_nandbiterrs: verify_page
> [   49.136808] mtd_nandbiterrs: Successfully corrected 5 bit errors per subpage
> [   49.140764] mtd_nandbiterrs: Inserted biterror @ 1/2
> [   49.147807] mtd_nandbiterrs: rewrite page
> [   49.153607] mtd_nandbiterrs: read_page
> [   49.157268] mtd_nandbiterrs: Read reported 2 corrected bit errors
> [   49.160294] mtd_nandbiterrs: verify_page
> [   49.166496] mtd_nandbiterrs: Successfully corrected 6 bit errors per subpage
> [   49.170452] mtd_nandbiterrs: Inserted biterror @ 1/0
> [   49.177498] mtd_nandbiterrs: rewrite page
> [   49.183253] mtd_nandbiterrs: read_page
> [   49.186974] mtd_nandbiterrs: Read reported 2 corrected bit errors
> [   49.189983] mtd_nandbiterrs: verify_page
> [   49.196194] mtd_nandbiterrs: Successfully corrected 7 bit errors per subpage
> [   49.200140] mtd_nandbiterrs: Inserted biterror @ 2/6
> [   49.207182] mtd_nandbiterrs: rewrite page
> [   49.212895] mtd_nandbiterrs: read_page
> [   49.216671] mtd_nandbiterrs: Read reported 3 corrected bit errors
> [   49.219670] mtd_nandbiterrs: verify_page
> [   49.225872] mtd_nandbiterrs: Successfully corrected 8 bit errors per subpage
> [   49.229827] mtd_nandbiterrs: Inserted biterror @ 2/5
> [   49.236871] mtd_nandbiterrs: rewrite page
> [   49.242629] mtd_nandbiterrs: read_page
> [   49.246348] mtd_nandbiterrs: error: read failed at 0x0
> [   49.249356] mtd_nandbiterrs: After 9 biterrors per subpage, read reported
> error -74
> [   49.257958] mtd_nandbiterrs: finished successfully.
> [   49.262029] ==================================================
> #

This is not the intended behavior. The reporting is wrong and should
report an increasing number of bitflips instead of 1, 1, 1, 2, 2, 2, 2,
3.

With this behavior, wear levelling will not work correctly.

This is not related to Gabor's changes, but I believe this should be
updated otherwise it does not make much sense to increase the strength.

Gabor, can you look into it? Both patches look fine otherwise, thanks a
lot!

Miquèl