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    SubjectRe: [PATCH] platform/x86: fujitsu-laptop: Revert UNSUPPORTED_CMD back to an int
    On Sat, Mar 10, 2018 at 09:43:53PM +0100, Micha?? K??pie?? wrote:
    > UNSUPPORTED_CMD was previously 0x80000000 (int), but commit 819cddae7cfa
    > ("platform/x86: fujitsu-laptop: Clean up constants") changed it into an
    > unsigned long due to BIT() being used to define it. As call_fext_func()
    > returns an int, 0x80000000 would get type promoted when compared to an
    > unsigned long, which on a 64-bit system would cause it to become
    > 0xffffffff80000000 due to sign extension. This causes one logical
    > condition in fujitsu-laptop to always be true and another one to always
    > be false on 64-bit systems. Fix this by reverting UNSUPPORTED_CMD back
    > to an int.
    >
    > This patch fixes the following smatch warnings:
    >
    > drivers/platform/x86/fujitsu-laptop.c:763 acpi_fujitsu_laptop_leds_register() warn: always true condition '(call_fext_func(device, ((1 << (12)) | (1 << (0))), 2, (1 << (16)), 0) != (1 << (31))) => (s32min-s32max != 2147483648)'
    > drivers/platform/x86/fujitsu-laptop.c:816 acpi_fujitsu_laptop_add() warn: impossible condition '(priv->flags_supported == (1 << (31))) => (0-2147483647,18446744071562067968-u64max == 2147483648)'
    >
    > Fixes: 819cddae7cfa ("platform/x86: fujitsu-laptop: Clean up constants")
    > Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
    > Signed-off-by: Micha?? K??pie?? <kernel@kempniu.pl>
    > ---
    > This fixes a bug introduced by a commit queued for 4.17, so it needs to
    > be applied on top of for-next.
    >
    > drivers/platform/x86/fujitsu-laptop.c | 2 +-
    > 1 file changed, 1 insertion(+), 1 deletion(-)
    >
    > diff --git a/drivers/platform/x86/fujitsu-laptop.c b/drivers/platform/x86/fujitsu-laptop.c
    > index 13bcdfea5349..6f4a55a53ced 100644
    > --- a/drivers/platform/x86/fujitsu-laptop.c
    > +++ b/drivers/platform/x86/fujitsu-laptop.c
    > @@ -85,7 +85,7 @@
    > #define FUNC_BACKLIGHT (BIT(12) | BIT(2))
    >
    > /* FUNC interface - responses */
    > -#define UNSUPPORTED_CMD BIT(31)
    > +#define UNSUPPORTED_CMD 0x80000000
    >
    > /* FUNC interface - status flags */
    > #define FLAG_RFKILL BIT(5)

    This looks like a sensible, succinct solution to the regression.

    Reviewed-by: Jonathan Woithe <jwoithe@just42.net>

    Regards
    jonathan

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