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    SubjectRe: [RFC][MMC] Buggy cards need to leave programming state
    On Mon, Dec 26, 2005 at 02:19:52PM +0100, Pierre Ossman wrote:
    > I've gotten two reports for cards that just crap out during write
    > transfers. The solution I've given them is to make the mmc block layer
    > wait for the card to leave programming state.

    This is interesting. In the specs I have, they indicate that the
    correct behaviour of a MMC card for CMD24 (write block) is that
    when its write buffer is full, it will hold the DAT signal low to
    indicate "busy" to the host controller.

    Now, the ARM MMCI holds the data path in the "BUSY" state while
    the MMC card asserts this indication, so we don't complete the
    data transfer until the card says it's not busy.

    For PXAMCI, it looks like we aren't waiting for the indication
    from the host which tells us that the "BUSY" has cleared.

    Does wbsd wait for the DAT busy signal to de-assert?

    However, I do note that from the October dump, the card is
    reporting that it is ready for more data (bit 8):

    MMC: req done (0d): 0: 00000f00 4b000000 00000000 00000000

    whereas it's impossible to tell with the November dump because
    the useful information has been edited out. Hence the November
    dump is rather useless.

    Russell King
    Linux kernel 2.6 ARM Linux -
    maintainer of: 2.6 Serial core
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      Last update: 2005-12-26 20:15    [W:0.020 / U:23.740 seconds]
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