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    SubjectRe: [PATCH] ACPI: fix acpi_power_off lockdep splat
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    On Sunday, July 03, 2011, Florian Mickler wrote:
    > On Sun, 3 Jul 2011 08:58:41 +0200
    > "Rafael J. Wysocki" <rjw@sisk.pl> wrote:
    >
    > > On Saturday, July 02, 2011, Andrea Righi wrote:
    > > > Implement acpi_os_create_lock() as a C-preprocessor macro to assign
    > > > unique lock_class_key to dynamically allocated locks and suppress wrong
    > > > lockdep warnings.
    > > >
    > > > This fixes:
    > > > https://bugzilla.kernel.org/show_bug.cgi?id=38152
    > > >
    > > > Reported-by: Borislav Petkov <bp@alien8.de>
    > > > Signed-off-by: Andrea Righi <andrea@betterlinux.com>
    > >
    > > So, how exactly does it work?
    >
    > The spin_lock_init macro stringifies it's argument and uses that as a
    > name for the lock in the debugging.
    >
    > By re-executing spin_lock_init (have not checked if that harms
    > anything, but it should be ok) in the _macro_ the key changes from
    > "lock" for all three locks to the actual argument
    > "&acpi_gbl_global_lock_pending_lock", "&acpi_gbl_gpe_lock" or
    > "&acpi_gbl_hardware_lock".

    OK, thanks for the explanation.

    The proposed solution doesn't seem to be extremely straightforward,
    but perhaps it's the simplest one. I need to think about it a bit more.

    Thanks,
    Rafael


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