Re: [PATCH] platform/x86: ideapad-laptop: Do not warn if KBLC reports no backlight

["Mark Pearson" <mpearson-lenovo@squebb.ca>]

On Sat, Nov 7, 2026, at 9:49 AM, Rong Zhang wrote:
> Hi Punnay,
>
> On Sat, 2026-11-07 at 19:35 +0530, Punnay Sharma wrote:
>> On probe, the driver asks KBLC for the keyboard backlight type and
>> warns about any result other than 0x5 or 0x7.
>> 
>> The LOQ 15IRX10 with an RGB keyboard returns 0x1. Its KBLC sets bit 0
>> in every result, and sets bit 2 for the type query only if the EC field
>> GZ35 is 0. On this model GZ35 is not 0, and a separate USB controller
>> (048d:c693) drives the keyboard lights. So 0x1 means that KBLC controls
>> no keyboard backlight, but the driver logs on every boot:
>> 
>>   ideapad_acpi VPC2004:00: Unknown keyboard type: 1
>> 
>> Add KBD_BL_NONE_TYPE for 0x1 and do not warn about it.
>> 
>> Tested on a Lenovo LOQ 15IRX10 (BIOS R3CN44WW).
>
> +CC Artem.
>
> It seems that some devices provides functional KBLC despite
> KBD_BL_QUERY_TYPE returns 0x1. See
> https://bugzilla.kernel.org/show_bug.cgi?id=221198
>
> Mark, Derek, could you check the documentation about keyboard backlight
> type?
>
> Thanks,
> Rong
>
>> 
>> Signed-off-by: Punnay Sharma <punnaysharma805@gmail.com>
>> ---
>> KBD_BL_NONE_TYPE is placed last to avoid a conflict with Rong Zhang's
>> pending keyboard backlight series.
>> 
>> The same warning appears on other models, e.g. LOQ 15AHP10 [1] and
>> Legion 5 Pro 16ACH6H [2].
>> 
>> [1] https://lore.kernel.org/all/3f03931e7eafcb1781ca3cf922e588ab57caadcf@lavx.hu/
>> [2] https://github.com/johnfanv2/LenovoLegionLinux/issues/336
>> 
>>  drivers/platform/x86/lenovo/ideapad-laptop.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>> 
>> diff --git a/drivers/platform/x86/lenovo/ideapad-laptop.c b/drivers/platform/x86/lenovo/ideapad-laptop.c
>> index fcb5ed7035f5..eb4158bed264 100644
>> --- a/drivers/platform/x86/lenovo/ideapad-laptop.c
>> +++ b/drivers/platform/x86/lenovo/ideapad-laptop.c
>> @@ -148,6 +148,7 @@ enum {
>>  #define KBD_BL_QUERY_TYPE		0x1
>>  #define KBD_BL_TRISTATE_TYPE		0x5
>>  #define KBD_BL_TRISTATE_AUTO_TYPE	0x7
>> +#define KBD_BL_NONE_TYPE		0x1	/* No backlight through KBLC */
>>  
>>  #define KBD_BL_COMMAND_GET		0x2
>>  #define KBD_BL_COMMAND_SET		0x3
>> @@ -2246,7 +2247,7 @@ static int ideapad_check_features(struct ideapad_private *priv)
>>  			} else if (val == KBD_BL_TRISTATE_AUTO_TYPE) {
>>  				priv->features.kbd_bl = true;
>>  				priv->kbd_bl.type = KBD_BL_TRISTATE_AUTO;
>> -			} else {
>> +			} else if (val != KBD_BL_NONE_TYPE) {
>>  				dev_warn(&priv->platform_device->dev,
>>  					 "Unknown keyboard type: %lu",
>>  					 val);
>> 
>> base-commit: c339f4010dea8b0d754f84ace70cd1b089878ef8

Afraid I don't have any documentation handy, but I reached out to the Thinkbook team (using the BZ ticket) as I have some contacts there and they might be able to help. Will see if I hear back.

Mark