On Friday, January 16, 2015 at 07:35:11 PM, Pavel Machek wrote: > Hi! > > > > > -#define CONFIG_ENV_IS_NOWHERE > > > > > > > > #define CONFIG_ENV_SIZE 4096 > > > > > > > > +#define CONFIG_ENV_IS_IN_MMC > > > > +#define CONFIG_SYS_MMC_ENV_DEV 0/* device 0 */ > > > > +#define CONFIG_ENV_OFFSET 512/* just after the MBR */ > > > > + > > > > > > Would it make sense to make environment bigger (64K?) at this point, > > > and enabling the redundant environment option, so that one bad block > > > does not bring the whole device down? > > > > Do you think you'll ever have more than a 4KiB of text data in the env ? > > I can see a reason for some 16 KiB environment, but that's the > > > > ceiling. > > We have hit 4KiB size already, and I believe we are over 8KiB, > even. wagabuibui loads a lot of small files from flash. > > So if 16KiB is acceptable, lets do that.
16KiB is fine by me, though I'm not quite sure how you managed to stuff 8KiB full of env ;-) > > Usually, the env only has to be a few KiB and it's size has to be > > multiple of the underlying device's erase block. But in case of SD card, > > there are no explicit erase blocks exported to the user, all is hidden > > by the controller in the SD card and gives an illusion of a device which > > has 512b > > blocks and > > Allocation unit is usually 2, 4, 6, 8, 12 or 16 MiB on recent flash > cards. It is field in uSD card structure somewhere. We could choose > 24MiB, to have GCD, but... see: > > https://wiki.linaro.org/WorkingGroups/KernelArchived/Projects/FlashCardSurv > ey OK, this is even more precise. Thanks for the link. > > the user doesn't care for bad block management. Since the controller in > > the card does the bad block management and wear leveling/relocation of > > blocks, it also means that in case the controller did fail to provide > > the block which contains env, the whole card would already be in a very > > bad state. > > Bad block management means you don't get errors during write, but you > can still get errors during read. That in fact depends on the BBM implementation, but in case you get error during read, it's usually a game over kind of situation. But I agree. Best regards, Marek Vasut _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
