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SubjectRe: [PATCH] Default keyboard LEDs
Samuel Thibault wrote:
> In many cases, one prefers to have e.g. the NumLock on by default. In
> many cases, one doesn't want to have it by default, e.g. on laptops.
> Distributions actually have a very hard time trying to set this
> correctly after the kernel boot, and that doesn't work for new consoles
> that are created via the openvt(1) command anyway. This hence adds a
> keyboard.default_leds boot parameter that permits to configure the
> default keyboard LEDs.
> Signed-off-by: Samuel Thibault <>
> Actually, what would be perfect would be to use the configuration that
> the BIOS sets at boot by default. That is device-dependent, however.

It is, but it can be read out either by INT calls at initialization
time, or by reading out the byte at physical address 0x417:

Size: BYTE
SeeAlso: MEM 0040h:0018h,INT 16/AH=02h,MEM 0040h:0096h

Bitfields for keyboard status flags 1:
Bit(s) Description (Table M0010)
7 INSert active
6 Caps Lock active
5 Num Lock active
4 Scroll Lock active
3 either Alt pressed
2 either Ctrl pressed
1 Left Shift pressed
0 Right Shift pressed
SeeAlso: #M0011,#00587

The same information is available through INT 16h, AH=02h.


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