Hello all, I have a question concerning the "au" size of a SD Card. I have an old Kingston 64MB SD-Card and lately I have noticed this kernel message when I use the card: mmc0: SD Status: Invalid Allocation Unit size. This is due to the following commit: commit b63b5e819d5b21ae493c17c356018ffa98d3ee1c Author: Alan Cox <alan@xxxxxxxxxxxxxxx> Date: Mon Jul 2 18:55:13 2012 +0100 mmc: core: correct invalid error checking >From the "SD Specifications, Part 1, Physical Layer Specification", * AU_SIZE This 4-bit field indicates AU Size and the value can be selected from 16 KB. AU_SIZE Value Definition ------- ---------------- 0h Not Defined 1h 16 KB 2h 32 KB 3h 64 KB 4h 128 KB 5h 256 KB 6h 512 KB 7h 1 MB 8h 2 MB 9h 4 MB Ah 8 MB Bh 12 MB Ch 16 MB Dh 24 MB Eh 32 MB Fh 64 MB Also in the specification is this note: Sector: is the unit that is related to the erase commands. Its size is the number of blocks that will be erased in one portion. The size of a sector is fixed for each device. The information about the sector size (in blocks) is stored in the CSD. Note that if the card specifies AU size, sector size should be ignored. And this: * SECTOR_SIZE This field is fixed to 7Fh, which indicates 64 KBytes. This value does not relate to erase operations. High Capacity and Extended Capacity cards indicate memory boundary by AU size and this field should not be used. So, if an au size of 0 is reported wouldn't the erase size be the sector size? If nothing else I think the test needs to be adjusted to not report the error for an au size of 0. Regards, Hartley -- 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
