Re: [PATCH] platform/x86: thinkpad_acpi: add adaptive_kbd_modes parameter

From: BjÃrn Mork
Date: Sun Nov 25 2018 - 10:42:03 EST


Eric Wong <e@xxxxxxxxx> writes:
> BjÃrn Mork <bjorn@xxxxxxx> wrote:
>
>> And then I believe you have a busy loop here:
>>
>> > @@ -3815,20 +3838,20 @@ static int adaptive_keyboard_set_mode(int new_mode)
>> >
>> > static int adaptive_keyboard_get_next_mode(int mode)
>> > {
>> > - size_t i;
>> > - size_t max_mode = ARRAY_SIZE(adaptive_keyboard_modes) - 1;
>> > -
>> > - for (i = 0; i <= max_mode; i++) {
>> > - if (adaptive_keyboard_modes[i] == mode)
>> > - break;
>> > - }
>> > + int max_mode = fls(adaptive_kbd_modes);
>> > + int new_mode = mode >= max_mode ? HOME_MODE : mode + 1;
>> >
>> > - if (i >= max_mode)
>> > - i = 0;
>> > - else
>> > - i++;
>> > + /* make sure the new mode is allowed by the user */
>> > + while (!(adaptive_kbd_modes & (1 << new_mode))) {
>> > + new_mode++;
>> > + if (new_mode > max_mode)
>> > + new_mode = HOME_MODE;
>> >
>> > - return adaptive_keyboard_modes[i];
>> > + /* maybe the user disabled all other modes: */
>> > + if (new_mode == mode)
>> > + return mode;
>> > + }
>> > + return new_mode;
>> > }
>
> Not a busy loop, since new_mode will reset at HOME_MODE (0)
> and then it'll hit "new_mode == mode" and remain locked in
> to the current mode.

Right. I see it now. Thanks for explaining.

I guess I was expecting a complete loop bypass ala

if (!max_mode)
return mode:

but your solution will of course work just as fine.



BjÃrn