From: Sebastian Reichel <sre@kernel.org>
To: David Stephenson <git@davidstephenson.net>
Cc: platform-driver-x86@vger.kernel.org, Hans de Goede <hansg@kernel.org>
Subject: Re: [PATCH] platform: arm64: thinkpad-t14s-ec: don't send KEY_KBDILLUMTOGGLE on Fn+Space
Date: Tue, 1 Sep 2026 17:24:03 +0200 [thread overview]
Message-ID: <apbt8k0IH2U28-Cm@venus> (raw)
In-Reply-To: <20260825193556.133277-1-git@davidstephenson.net>
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Hi,
On Tue, Aug 25, 2026 at 07:36:21PM +0000, David Stephenson wrote:
> On the T14s, the EC already steps the keyboard backlight when you press
> Fn+Space: off, then low, then high.
>
> We report that change with t14s_kbd_bl_update() (brightness_hw_changed).
> We then also send KEY_KBDILLUMTOGGLE.
>
> The extra key is the problem. Desktops treat it as "please toggle the
> light." GNOME calls Keyboard.Toggle() and changes the LED itself. That
> fights the EC's three steps. The on-screen bar also stays empty,
> because Toggle() always returns 0%.
>
> thinkpad_acpi on x86 already skips the key when the firmware changed
> the light. It only uses brightness_hw_changed. Do the same here: keep
> the LED update, do not send KEY_KBDILLUMTOGGLE.
>
> Tested on a Lenovo ThinkPad T14s Gen 6 (21N1, Snapdragon X Elite) with
> GNOME. After this change the OSD bar tracks off / 50% / 100%.
>
> Signed-off-by: David Stephenson <git@davidstephenson.net>
> ---
Reviewed-by: Sebastian Reichel <sre@kernel.org>
Greetings,
-- Sebastian
> drivers/platform/arm64/lenovo-thinkpad-t14s.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/platform/arm64/lenovo-thinkpad-t14s.c b/drivers/platform/arm64/lenovo-thinkpad-t14s.c
> index 5590302a5..22d20a907 100644
> --- a/drivers/platform/arm64/lenovo-thinkpad-t14s.c
> +++ b/drivers/platform/arm64/lenovo-thinkpad-t14s.c
> @@ -488,8 +488,14 @@ static irqreturn_t t14s_ec_irq_handler(int irq, void *data)
> case T14S_EC_EVT_NONE:
> break;
> case T14S_EC_EVT_KEY_FN_SPACE:
> + /*
> + * Firmware already cycles the keyboard backlight
> + * (off / low / high). Notify userspace through the LED
> + * class only. Emitting KEY_KBDILLUMTOGGLE as well makes
> + * desktop environments toggle the LED a second time.
> + */
> t14s_kbd_bl_update(ec);
> - fallthrough;
> + break;
> case T14S_EC_EVT_KEY_FN_F4:
> case T14S_EC_EVT_KEY_FN_F7:
> case T14S_EC_EVT_KEY_FN_4:
> --
> 2.55.0
>
>
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prev parent reply other threads:[~2026-09-01 15:24 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-25 19:36 [PATCH] platform: arm64: thinkpad-t14s-ec: don't send KEY_KBDILLUMTOGGLE on Fn+Space David Stephenson
2026-08-26 9:09 ` Hans de Goede
2026-09-01 15:24 ` Sebastian Reichel [this message]
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