linux-kernel - Re: [PATCH] platform/x86: dell-laptop: Fix bogus keyboard backlight sysfs interface

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Message-ID: <CAHp75VdVyxpRjahy2rLmMD2wpCwuMRZ_K+U1ALfMhmveZFqPMw@mail.gmail.com>
Date:   Fri, 16 Jun 2017 13:06:38 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Pali Rohár <pali.rohar@...il.com>
Cc:     Kai-Heng Feng <kai.heng.feng@...onical.com>,
        Matthew Garrett <mjg59@...f.ucam.org>,
        "dvhart@...radead.org" <dvhart@...radead.org>,
        Platform Driver <platform-driver-x86@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] platform/x86: dell-laptop: Fix bogus keyboard backlight
 sysfs interface

On Fri, Jun 16, 2017 at 10:52 AM, Pali Rohár <pali.rohar@...il.com> wrote:
> On Friday 16 June 2017 15:35:39 Kai-Heng Feng wrote:

>> -     if (kbd_token_bits != 0 || ret == 0)
>> +     /*
>> +      * If KBD_LED_OFF_TOKEN is the only token,
>> +      * consider there is no keyboard backlight.
>> +      */
>> +     if ((kbd_token_bits & ~BIT(5)) != 0 || ret == 0)
>
> Should not this check to be rather:
>
> (kbd_token_bits != 0 && (kbd_token_bits & BIT(KBD_LED_OFF_TOKEN)) != BIT(KBD_LED_OFF_TOKEN))
>
> To express that we have at least one token at it is different from
> KBD_LED_OFF_TOKEN token?

Isn't the same to

(kbd_token_bits ^ BIT(KBD_LED_OFF_TOKEN))

?

-- 
With Best Regards,
Andy Shevchenko