Re: Why does printk helps PCMCIA card to initialise?

From: David Hinds (dhinds_at_sonic.net)
Date: 02/22/05

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    Date:	Tue, 22 Feb 2005 14:34:48 -0800
To: Russell King <rmk@arm.linux.org.uk>, torvalds@osdl.org

    On Mon, 21 Feb 2005, Linus Torvalds wrote:
    > On Mon, 21 Feb 2005, Russell King wrote:
    > >
    > > In cs.c, alloc_io_space(), find the line:
    > >
    > > if (*base & ~(align-1)) {
    > >
    > > delete the ~ and rebuild. This may resolve your problem.
    >
    > Unlikely. The code is too broken for words.

    The original code is correct; you are misinterpreting the meaning of
    the "align" variable here. PCMCIA cards can request a specific base
    IO address, and can also specify how many IO address lines they
    decode. The number of decoded lines determines a maximal alignment
    restriction for a card; if it only decodes 3 lines, then it should not
    reasonably ask for an IO region with more specificity than being on an
    8 port boundary. The "align" variable here holds this alignment. The
    "oddness" here is that the card is providing conflicting information,
    that it needs IO ports at a specific address, but is only decoding 3
    address lines (i.e. align=8).

    The names of "base" and "align" have the expected meanings when a card
    only specifies one or the other. It's only for the case where both
    are specified that the meaning is complicated. Then, "base" is more
    like an offset into a block that has "align" alignment

    Given an "odd" request for a base=0x260 and align=8, the allocator
    promotes this to align=0x400, and would allow addresses 0x260, 0x660,
    0xa60, 0xe60, etc, subject to restrictions in /etc/pcmcia/config.opts.

    The real problem here is that all the IO address ranges the card
    claims to support were unavailable. I'd first try adding:

      include port 0x0600-0x07ff

    to /etc/pcmcia/config.opts to give the allocator more flexibility in
    choosing port ranges.

    -- Dave
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