Re: MMC quirks relating to performance/lifetime.

Andrei Warkentin
2011-02-12T17:33:14Z

On Sat, Feb 12, 2011 at 11:05 AM, Arnd Bergmann <arnd@arndb.de> wrote:
> On Friday 11 February 2011 23:33:42 Andrei Warkentin wrote:
>> On Wed, Feb 9, 2011 at 3:13 AM, Arnd Bergmann <arnd@arndb.de> wrote:
>
>> Yes, this is a Toshiba card. I've sent the patch as a reply to Linus' email.
>>
>> cid - 02010053454d3332479070cc51451d00
>> csd - d00f00320f5903ffffffffff92404000
>> erase_size - 524288
>> fwrev - 0x0
>> hwrev - 0x0
>> manfid - 0x000002
>> name - SEM32G
>> oemid - 0x0100
>> preferred_erase_size - 2097152
>
> Very interesting. So the manfid is the same as on most Kingston cards,
> but the oemid is different. Most cards have a two-letter ASCII code
> in there, 0x544d ("TM") on Kingston cards, and I always assumed that
> this stood for "Toshiba Memory".
>
> What is even stranger is the size value (among other fields) in the CSD,
> the card claims a size of exactly 32GB, which I find hard to believe,
> given that there are always some bad and reserved blocks.
>
> Are you sure that the card you have is authentic? I've heard a lot about
> fake USB sticks advertising a size that is much larger than the actual
> flash inside of them.
>
> Also this is the first card that I see advertise an allocation unit
> size of 2MB (preferred_erase_size), all other cards seem to advertise
> 4 MB these days, even if they actually have 2 or 8 MB.
>
>        Arnd
>

This is a Toshiba eMMC part. It is 32GB as far as the OS can see and access.