View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0005981 | fsimx_Linux | Kernel | public | 2023-11-06 11:56 | 2023-11-06 12:51 |
| Reporter | gerbach | Assigned To | |||
| Priority | normal | Severity | feature | Reproducibility | always |
| Status | resolved | Resolution | fixed | ||
| Product Version | fsimx8mp-Y2023.09 | ||||
| Target Version | fsimx8m-next | Fixed in Version | fsimx8mm-Y2023.10 | ||
| Summary | 0005981: Don't use nand-on-flash-bad block table for fsimx8mm | ||||
| Description | Disable the Bad Block Table (BBT) because the BBT uses the 4 last PEBs of nand flash, which overwrites UBIFS. BBT was disabled for fsimx6. There is not so much performance penalty due to that. There is no impact on the reliability of a flash because this is just a table of bad blocks which is otherwise recreated in the ram at every boot. The MTD layer supplies upper layers (including UBI) with information about bad PEBs. It keeps so-called bad block table in RAM, which is usually 1 bit per PEB. When the driver initializes, it has to build this table by scanning whole flash media, which normally includes reading OOB area of 1st NAND page of each PEB. This takes time and may be improved by using on-flash BBT (bad block table). In this case the bad PEB map is stored on flash and MTD does not have to do any scanning. See the nand-on-flash-bbt dts flag in the Linux source codes. But note, bad PEB scanning is usually minor comparing to the UBI scan time, so on-flash BBT is not probably going to give much. | ||||
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