ALSA update broke Sparc

From: David S. Miller (davem_at_davemloft.net)
Date: 08/28/04

  • Next message: Andrew Morton: "Re: page fault scalability patch final : i386 tested, x86_64 support added" 
    Date:	Fri, 27 Aug 2004 18:36:46 -0700
To: linux-kernel@vger.kernel.org

    Each platform uses a different number of arguments for
    io_remap_page_range(), so you can't just blindly call it
    from generic code.

    However, sound/core/pcm_native.c is doing exactly that.

    The reason each platform takes a different number of
    args is that the "unsigned long" base address argument
    is only 32-bits on 32-bit platforms yet on some of
    such platforms I/O and physical memory addresses
    are larger than 32-bits.

    Sparc and Sparc64 use a "space" argument to provide this
    upper 32-bits of information.

    Also, what this PCM mmap'ing code is trying to do
    is take I/O addresses and remap them into the process
    address space. pci_resource_start() values are not necessarily
    suitable for passing around as physical addresses. These
    things are well defined when used with ioremap() but
    that is it. I don't know if we've defined it such that
    passing these into io_remap_page_range() can be expected
    to work.

    In fact, because of the sparc 32-bit issue, I know it won't
    work. You'll need to have the full resource structure
    available, as that's where we hide the upper 32-bits of
    the physical address on sparc32.

    This is really non-portable, what the PCM code is doing.
    I would suggest, for the time being, to pass resources
    around and then have an arch-defined macro which takes
    the resource pointer and makes the appropriate io_remap_page_range()
    call.

    Can I make a small formal request of the ALSA folks? Can you
    at least setup a cross-compiler to make sure your ALSA merges
    don't explode on sparc64? As it stands, 1 out of every 2 ALSA
    merges breaks the build on that platform.
    -
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