On Fri, Jul 15, 2022 at 05:15:36PM +0200, Alexander Lobakin wrote:
> The bitops compile-time optimization series revealed one more
> problem in olpc-xo1-sci.c:send_ebook_state(), resulted in GCC
> warnings:
>
> arch/x86/platform/olpc/olpc-xo1-sci.c: In function 'send_ebook_state':
> arch/x86/platform/olpc/olpc-xo1-sci.c:83:63: warning: logical not is only applied to the left hand side of comparison [-Wlogical-not-parentheses]
> 83 | if (!!test_bit(SW_TABLET_MODE, ebook_switch_idev->sw) == state)
> | ^~
> arch/x86/platform/olpc/olpc-xo1-sci.c:83:13: note: add parentheses around left hand side expression to silence this warning
>
> Despite this code working as intended, this redundant double
> negation of boolean value, together with comparing to `char`
> with no explicit conversion to bool, makes compilers think
> the author made some unintentional logical mistakes here.
> Make it the other way around and negate the char instead
> to silence the warnings.
>
> Fixes: d2aa37411b8e ("x86/olpc/xo1/sci: Produce wakeup events for buttons and switches")
> Cc: stable@xxxxxxxxxxxxxxx # 3.5+
> Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Reviewed-and-tested-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> Signed-off-by: Alexander Lobakin <alexandr.lobakin@xxxxxxxxx>
Applied, thanks!
> ---
> arch/x86/platform/olpc/olpc-xo1-sci.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/platform/olpc/olpc-xo1-sci.c b/arch/x86/platform/olpc/olpc-xo1-sci.c
> index f03a6883dcc6..89f25af4b3c3 100644
> --- a/arch/x86/platform/olpc/olpc-xo1-sci.c
> +++ b/arch/x86/platform/olpc/olpc-xo1-sci.c
> @@ -80,7 +80,7 @@ static void send_ebook_state(void)
> return;
> }
>
> - if (!!test_bit(SW_TABLET_MODE, ebook_switch_idev->sw) == state)
> + if (test_bit(SW_TABLET_MODE, ebook_switch_idev->sw) == !!state)
> return; /* Nothing new to report. */
>
> input_report_switch(ebook_switch_idev, SW_TABLET_MODE, state);
> --
> 2.36.1
