Re: [PATCH v1] platform/x86: redmi-wmi: add display-switch key binding

["Ilya Gladyshev" <ilya.gladyshev@linux.dev>]

On 9/30/26 02:42, Антон Карасев wrote:
> Tested-by: Anton Karasev <uselessfire@gmail.com>

Thanks!

> Tested on the reporting machine (Xiaomi Redmi Book Pro 16 2024, DMI
> XIAOMI/TM2309, BIOS RMAMT6B0P0B0B), kernel 7.2.7, by building redmi-wmi
> from mainline with this patch applied and loading it in place of the
> in-tree module.
> > Before: pressing the display-switch key gave "Unknown WMI event with
> payload 257" and no input event at all.
> > After: the key reports KEY_SWITCHVIDEOMODE. The keymap read back from the
> device contains both forms now:
> >    scancode 0x101 -> 227
>    scancode 0x10101 -> 227
> > and the desktop reacts to the key (KDE opens its display-switch menu).
> The other hotkeys are unaffected: 0x201 -> KEY_SELECTIVE_SCREENSHOT,
> 0x1b01 -> KEY_CONFIG, 0x11801/0x11901 -> KEY_ASSISTANT all still work,
> and nothing new showed up in dmesg.
> > Two notes that did not fit the fix, in case they are useful:
> > 1. The merge series "Merge redmi-wmi into bitland-mifs-wmi" (v6,
>     20260929134503.17249-1-qby140326@gmail.com) drops redmi-wmi, and its
>     combined keymap only carries the long form:

Yes, if Mingyou's patch lands first, I will rebase my patch to target the
bitland-mifs-wmi driver.

>       { KE_KEY, BI_HOTKEY_CODE(WMI_EVENT_RESERVED_1, 1, 0), {
> KEY_SWITCHVIDEOMODE } },
> >     With WMI_EVENT_RESERVED_1 = 1 and WMI_EVENT_TYPE_HOTKEY = 1 that expands
>     to 0x00010101; the short 0x00000101 has no entry there. If that series
>     lands, this fix is lost again on this model. I am replying to that
>     thread separately.
>
> 2. Two payloads are still unhandled here: 0x00000901 and 0x00010901. They
>     are not key presses -- the EC echoes back the Caps Lock LED state that
>     the host itself has just set (third byte 1 = on, 0 = off, the same
>     scheme as the Fn Lock events). Verified by switching between windows
>     with per-window keyboard layouts, which changes the LED without anyone
>     touching the key: the events still arrive, 200-500 ms after the LED
>     change. On a system where Caps Lock switches the layout this is a
>     steady stream of dev_dbg lines; KE_IGNORE would silence it.

IMO, it is better to leave such keycodes unhandled. In practice, dev_dbg()
is a no-op (it is a static key call), so there will be no noise in dmesg.

However, if some future board uses those payloads for something useful,
dev_dbg() will help extract them (just as in your case).

> Details and traces: https://bugzilla.kernel.org/show_bug.cgi?id=222062
> > Thanks for the quick fix!
> > Anton
> > вт, 29 сент. 2026 г. в 01:14, Ilya Gladyshev <ilya.gladyshev@linux.dev>:
>>
>> As reported on the mailing list [1], on the Xiaomi Redmi Book Pro 16
>> 2024, the display-switch key emits 0x101 as a WMI payload. Add a
>> mapping for it to the keymap.
>>
>> [1]: https://lore.kernel.org/all/CAFsq4KBXCB=aK8ENHx__6+RcC-ybT7eKjcgsa3TgcJ54x-PLEg@mail.gmail.com/
>>
>> Reported-by: Антон Карасев <uselessfire@gmail.com>
>> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=222062
>> Signed-off-by: Ilya Gladyshev <ilya.gladyshev@linux.dev>
>> ---
>>
>> This patch conflicts with the unification of redmi-wmi and
>> bitland-mifs-wmi [2]. However, that patch appears to be stuck for now,
>> so updating a single mapping in the old driver seems acceptable.
>>
>> Cc its author, Mingyou Chen.
>>
>> Also, I can only test that it doesn't break on my hardware, so any
>> additional testing is highly welcome.
>>
>> [2]: https://lore.kernel.org/all/20260816100813.300450-1-qby140326@gmail.com/
>> ---
>>   drivers/platform/x86/redmi-wmi.c | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/platform/x86/redmi-wmi.c b/drivers/platform/x86/redmi-wmi.c
>> index cc82ef502002..155777bf90f3 100644
>> --- a/drivers/platform/x86/redmi-wmi.c
>> +++ b/drivers/platform/x86/redmi-wmi.c
>> @@ -22,6 +22,7 @@ static const struct key_entry redmi_wmi_keymap[] = {
>>          {KE_KEY, 0x00000301,    {KEY_ALL_APPLICATIONS}},
>>          {KE_KEY, 0x00001b01,    {KEY_CONFIG}},
>>          {KE_KEY, 0x00011b01,    {KEY_CONFIG}},
>> +       {KE_KEY, 0x00000101,    {KEY_SWITCHVIDEOMODE}},
>>          {KE_KEY, 0x00010101,    {KEY_SWITCHVIDEOMODE}},
>>          {KE_KEY, 0x00001a01,    {KEY_REFRESH_RATE_TOGGLE}},
>>
>> --
>> 2.55.0
>>