UBI - disable subpage verify and use CONFIG_MTD_NAND_VERIFY_WRITE possible?

[Darwin Rambo]

Hello Artem,

Can you please clarify something for me?

http://www.linux-mtd.infradead.org/faq/ubi.html#L_subpage_verify_fail 

I read this note and still, CONFIG_MTD_NAND_VERIFY_WRITE is very useful for me. The question is, if I don't mind wasting a bit of flash, and configure UBI to not do subpage writes and put the EC and VID headers on separate pages (for example ubi.mtd=6,4096), does UBI then always do page writes and would CONFIG_MTD_NAND_VERIFY_WRITE then work reliably for me? Or are there other places in the code that might do subpage writes? So far it seems to work well for me with the verify on and no subpages for the headers. 

By the way, the standard nand_verify_buf() function in nand_base.c uses readb(chip->IO_ADDR_R) and doesn't use something like chip->ecc.read_page() to correct the data so this sounds like a bug to me. But I override this to do corrected reads anyways, which works better for SLC/MLC flash which can show one or more bit errors in a page read.

I apologize in advance if this is already documented somewhere.

Thanks.

Best regards,
Darwin


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