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    SubjectRe: [PATCH 14/29] memstick: remove the memstick_set_rw_addr
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    On Mon, 2010-10-25 at 08:55 -0700, Alex Dubov wrote:
    >
    > --- On Fri, 22/10/10, Maxim Levitsky <maximlevitsky@gmail.com> wrote:
    >
    > > From: Maxim Levitsky <maximlevitsky@gmail.com>
    > > Subject: [PATCH 14/29] memstick: remove the memstick_set_rw_addr
    > > To: "Alex Dubov" <oakad@yahoo.com>
    > > Cc: "Andrew Morton" <akpm@linux-foundation.org>, "LKML" <linux-kernel@vger.kernel.org>, "Maxim Levitsky" <maximlevitsky@gmail.com>
    > > Received: Friday, 22 October, 2010, 4:53 PM
    > > Remove this function, what was
    > > last user that did send the MS_TPC_SET_RW_REG_ADRS
    > > directly.
    > >
    > > Just invalidate the register window, and next register
    > > read/write will send that tpc automaticly.
    > >
    > > Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
    > > ---
    >
    > How is an obscure invalidate_reg_window function is any better than
    > explicit set_rw_addr? Total number of calls to either of them is exactly
    > the same.
    Nope.
    I just set the reg window where it should be: in register read/write
    functions.
    Here we tampered with register window by using another card structure,
    so we invalidate it. Simple.
    The point is that I send the register window update just before register
    read/write, and optionaly skip that if cached version matches the one I
    need.


    >
    > Sony state machine diagrams suggest that doing a precise set_rw_addr when
    > necessary is a good thing.
    And that exactly what I am doing.
    I am setting that window just before a register read/write.


    > The feature was originally conceived because
    > Sony intended to manufacture MSIO and hybrid devices, which might have very
    > large number of registers (hundreds). It was also supposed to help with
    > backward compatibility of devices, as well as with DRM functionality
    >
    > We know, at this point of time, that Sony is sort of loosing the format
    > war, so MSIO devices these days are very hard to come by. However, some
    > hybrid (Transfer Jet) and DRM-secured devices still exist and it is wise
    > to retain functionality which can help to operate those (I don't have full
    > details on their operation, but it doesn't mean we should forget them
    > outright).


    Best regards,
    Maxim Levitsky




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