Re: [PATCH 1/1 linux-next] ACPI / SBS: fix sparse warning

From: Sudip Mukherjee
Date: Mon Sep 29 2014 - 01:40:26 EST


On Sun, Sep 28, 2014 at 08:44:47PM +0200, Fabian Frederick wrote:
> Adding parentheses around expression to avoid:
> drivers/acpi/sbs.c:444:28: warning: dubious: !x & y
>
> Signed-off-by: Fabian Frederick <fabf@xxxxxxxxx>
> ---
> drivers/acpi/sbs.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/acpi/sbs.c b/drivers/acpi/sbs.c
> index 32aecea..a7a3edd 100644
> --- a/drivers/acpi/sbs.c
> +++ b/drivers/acpi/sbs.c
> @@ -441,7 +441,7 @@ static int acpi_ac_get_present(struct acpi_sbs *sbs)
> * The spec requires that bit 4 always be 1. If it's not set, assume
> * that the implementation doesn't support an SBS charger
> */
> - if (!(status >> 4) & 0x1)
> + if (!((status >> 4) & 0x1))

i think the logic changed over here.
it was !x & y , but now it has become !(x & y)
! is having higher priority than & so !x & y will mean ((!x) & y)

thanks
sudip
> return -ENODEV;
>
> sbs->charger_present = (status >> 15) & 0x1;
> --
> 1.9.1
>
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