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    SubjectRe: Linux-2.3.51, and the pre-2.4 series..


    On Sat, 11 Mar 2000, Richard Gooch wrote:
    > >
    > > It's due to the TI cardbus controllers not correctly sensing the
    > > power of the inserted card, so the higher level layers will try to
    > > apply 5V power and it goes to hell from there. I added code in
    > > 2.3.51 to notice when the power sense is wrong and force a new VS
    > > sense event.
    >
    > Argh! Does that mean 5V is being applied to 3V cards and said 3V cards
    > are being toasted?

    No. The controller has over-voltage protection, so it just means that it
    won't work.

    The problem is actually due to a unlucky interface between the low-level
    slot driver and the card services layer: there's a flag that says "I'm a
    3V card", but there is NOT a flag that says "I'm a 5V card". So what
    happened here is that
    - the cardbus controller did not report any voltages at all.
    - the low-level driver thus did not set the 3V flag.
    - cardservices thought that "not 3V" == "5V"
    - it didn't work.

    The fix in 2.3.51 is for the low-level driver to notice that neither the
    5V nor the 3V flags were set, and if that happens it will try to force a
    re-sense of the card.

    I've seen this with the TI1225, and it does not happen with my Ricoh
    controller in my Sony VAIO that I did most of the development on. So I
    think it's actually a buglet in the TI core.

    Linus


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