Re: [PATCH] input: Add new keyboard backlight control keys to match modern notebooks

From: Werner Sembach
Date: Tue May 30 2023 - 10:30:31 EST


Hi,

Am 30.05.23 um 15:33 schrieb Bastien Nocera:
On Tue, 2023-05-30 at 13:05 +0200, Werner Sembach wrote:
The old three KEY_KBDILLUM* keycodes don't reflect the current
situation
modern notebooks anymore. Especially the ones with RGB keyboards.

e.g.
- Clevo NL50NU has a toggle, an up, a down and a color-cycle key
- TongFang PH4ARX1 doesn't have a toggle key, but one that cycles
through
  off, half-brightness, and full-brightness.

Also, on some devices these keys are already implemented in firmware.
It
would still be nice if there is a way to let userspace know when one
of
these keys is pressed to display the OSD, but don't advice it to
actually
do anything. This is the intended purpose of the KEY_KBDILLUMCHANGE
define.

Signed-off-by: Werner Sembach <wse@xxxxxxxxxxxxxxxxxxx>
Can you please point to the user-space patches (or issues filed) that
would integrate the support for those keycodes, and make the key
presses do something?

I'm sorry to say that these don't exist yet. So I guess the process is similar to DRM uAPI additions? https://docs.kernel.org/gpu/drm-uapi.html#open-source-userspace-requirements


Has anyone tested that those keycodes are fit for purpose when mixed
with other brightness changes that don't happen through key presses?

Color control is not yet implemented in any DE afaik, so there is not yet a collision with the color cycle key.

For the brightness cycle key, I would assume that it functions the same as the brightness up key unless brightness == brightness max. In this case it sets brightness to 0. I don't see a logical collision here as brightness up and brightness down are already implemented just fine in most DEs


---
 include/uapi/linux/input-event-codes.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/uapi/linux/input-event-codes.h
b/include/uapi/linux/input-event-codes.h
index 022a520e31fc2..05287bf9a77f7 100644
--- a/include/uapi/linux/input-event-codes.h
+++ b/include/uapi/linux/input-event-codes.h
@@ -803,6 +803,10 @@
 #define BTN_TRIGGER_HAPPY39            0x2e6
 #define BTN_TRIGGER_HAPPY40            0x2e7
+#define KEY_KBDILLUMCYCLE              0x2e8
+#define KEY_KBDILLUMCOLORCYCLE         0x2e9
+#define KEY_KBDILLUMCHANGE             0x2ea
+
 /* We avoid low common keys in module aliases so they don't get
huge. */
 #define KEY_MIN_INTERESTING    KEY_MUTE
 #define KEY_MAX                        0x2ff