On Thu, Nov 18, 2010 at 4:33 PM, Ghorai, Sukumar <s-ghorai@xxxxxx> wrote: >> -----Original Message----- >> From: linux-omap-owner@xxxxxxxxxxxxxxx [mailto:linux-omap- >> owner@xxxxxxxxxxxxxxx] On Behalf Of Charles Manning >> Sent: Thursday, November 18, 2010 6:36 AM >> To: linux-omap@xxxxxxxxxxxxxxx >> Subject: No more software ECC in omap2.c NAND driver. Why? >> >> Between 2.6.35 and 2.6.36 there have need quite a few changes in the NAND >> driver, including a change from software to hardware ECC. >> >> The new code has hardware ECC forced on by: >> >> #define CONFIG_MTD_NAND_OMAP_HWECC >> >> I am surprised that this was done. Surely this should have been a Kconfig >> option to select either sw ECC or hw ECC? >> >> Does moving to hardware ECC to the exclusion of software ECC reduce >> functionality? > > [Ghorai] This is wrongly added by me, during last few patches. So I have > send the fix as you mentioned too as. > [PATCH] omap: nand: remove hardware ECC as default > > And please let me know still if it has any issue. For me it makes normal sw ECC page IO work, but for subpages to work I have to disable the prefetch option. > And I am re-working on the patches for the different ecc schema including > s/w, h/w or different, to pass it form board file. > >> >> Does the new hwecc scheme still support sub-page writes or does it only >> provide full page writes? If sub-page writes are lost then this has a >> ripple >> effect in breaking the way some UBI stuff works. > > [Ghorai] > 1. do you think this sub-page read/write support was there before, say in > 2.6.35? And breaks in 2.6.36? It certainly was there for sw ECC as we've been using UBI from 2.6.27 to 2.6.35 just fine. > 2. In that case would you please let know what are the size(s) used for > sub-page/read write? 512 bytes. -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
