Re: [PATCH v3 4/7] platform/x86: thinkpad_acpi: Detect auto-mode capability via MLCG

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

On Sat, Nov 14, 2026, at 12:48 PM, Qiling Zhu wrote:
> The upper bits of the MLCG return value carry capability information.
> Bit 20 indicates whether the EC supports the auto mode of the keyboard
> backlight (0 = manual levels only, 1 = auto mode available), as defined
> by the firmware.
>
> Record it in tp_features.kbdlight_auto, in preparation for using it to
> gate the auto-mode trigger registration and the LED suspend/resume
> skipping in subsequent changes.
>
> Link: 
> https://lore.kernel.org/r/CABxCQKuEP5wMSstO0MK1MhaqXTKrPhUSN3V2mrE_42j4cXsXZQ@mail.gmail.com
> Signed-off-by: Qiling Zhu <kmatzkaczor244@gmail.com>
> ---
>  drivers/platform/x86/lenovo/thinkpad_acpi.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/drivers/platform/x86/lenovo/thinkpad_acpi.c 
> b/drivers/platform/x86/lenovo/thinkpad_acpi.c
> index 657a19d11..681b340a1 100644
> --- a/drivers/platform/x86/lenovo/thinkpad_acpi.c
> +++ b/drivers/platform/x86/lenovo/thinkpad_acpi.c
> @@ -363,6 +363,7 @@ static struct {
>  		TP_HOTKEY_TABLET_USES_GMMS,
>  	} hotkey_tablet;
>  	u32 kbdlight:1;
> +	u32 kbdlight_auto:1;
>  	u32 light:1;
>  	u32 light_status:1;
>  	u32 bright_acpimode:1;
> @@ -5161,6 +5162,13 @@ static bool kbdlight_is_supported(void)
>  	}
> 
>  	vdbg_printk(TPACPI_DBG_INIT, "kbdlight MLCG returned 0x%x\n", status);
> +
> +	/*
> +	 * MLCG bit 20 indicates auto mode support: 0 = manual levels only,
> +	 * 1 = auto mode available (per the firmware definition).
> +	 */
> +	tp_features.kbdlight_auto = !!(status & BIT(20));
> +
>  	/*
>  	 * Guessed test for keyboard backlight:
>  	 *
> -- 
> 2.56.1

Looks good to me.
Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Mark