On Thursday 10 March 2011 21:45:07 Andrei Warkentin wrote: > > We can pre-initialize the page size to some common value > > (e.g. 16 KB for 4GB or larger cards, 4 KB for smaller than > > 4 GB), and use quirks to override it for cards where we > > know it's different. > > > > Even better. We have the "super page size" in the EXT_CSD. For example > for Sandisk it's 16KB, Toshiba is reporting 32KB, but we know that's > not right... Ok, that sounds good. I don't think we have anything like this for SD cards though, so we'd still need to make some reasonable assumption there. The one thing we know is that all SD cards should support writes of 32KB alignment, because that is the largest cluster size supported by FAT16 and FAT32. I have experimentally shown that most cards can reasonably do 16KB, and only few modern cards can do smaller than that. I also don't know what the effect of setting physical_block_size and/or io_min is, possibly it no longer works if they are larger than the MMU page size. Need to try this. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
