Messages in this thread | | | Date | Fri, 06 Feb 2015 10:28:53 +0100 | From | Richard Weinberger <> | Subject | Re: [PATCH] mtd: denali: Disable sub-page writes in Denali NAND driver |
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Am 06.02.2015 um 09:29 schrieb Ricard Wanderlof: > > On Thu, 5 Feb 2015, Graham Moore wrote: > >> Actually, we made this change to make UBIFS work. So, yes, the driver >> never worked for UBI. Worked fine for JFFS2, raw data. >> >> A customer reported an issue with ECC errors when using UBIFS on NAND >> flash with Altera SoC. >> >> We debugged it and found the ECC errors occur because the UBI subsystem >> is trying to write sub-pages in the NAND, but neither the NAND chip >> itself nor the Denali NAND controller support sub-page writes. > > Just a bit curious. > > It is not uncommon for controllers or chips not to support sub-page > writes. In that case however, the partition(s) used by UBI should be > formatted accordingly, i.e. using the appropriate --sub-page-size argument > to ubiformat (when formatting partitions on the system itself), or the > corresponding argument to ubinize (when preparing images offline). > > If that is done correctly, then the lack of subpage write capability is > not a problem per se (of course, the UBI EC and VID headers then take up > more space so less space is available for user data; on a flash with 2k > pages it is only 2k bytes per LEB that is lost however).
Yeah, but UBI automatically will use subpages unless you specify use the vid_hdr_offs parameter. IOW, if the driver advertises subpages UBI will use them.
Thanks, //richard
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