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

[Rong Zhang <i@rong.moe>]

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