Re: [PATCH] platform/x86: sony-laptop: Don't turn off 0x153 keyboard backlight during probe

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 12/13/22 14:03, Andy Shevchenko wrote:
> On Tue, Dec 13, 2022 at 2:29 PM Hans de Goede <hdegoede@redhat.com> wrote:
>>
>> The 0x153 version of the kbd backlight control SNC handle has no separate
>> address to probe if the backlight is there.
>>
>> This turns the probe call into a set keyboard backlight call with a value
>> of 0 turning off the keyboard backlight.
>>
>> Skip probing when there is no separate probe address to avoid this.
> 
> ...
> 
>> +       /*
>> +        * Only probe if there is a separate probe_base, otherwise the probe call
>> +        * is equivalent to __sony_nc_kbd_backlight_mode_set(0), resulting in
>> +        * the keyboard backlight being turned off.
>> +        */
>> +       if (probe_base) {
> 
> I'm wondering if it wouldn't be better to split this into the helper
> and hence just call it here.

The helper here is sony_call_snc_handle() which is not only used for
probing it is a generic helper.

Calling sony_call_snc_handle() with an argument of 0 is valid, specifically
this turns of the kbd backlight on the affected laptop models.

Which is a valid thing to do if the user requests it, but it is not a valid
thing to do as a "probe" to see if there is a kbd-backlight.

Regards,

Hans