[PATCH] Default keyboard LEDs

[PATCH] Default keyboard LEDs

[Samuel Thibault]

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 <samuel.thibault@ens-lyon.org>

---

Actually, what would be perfect would be to use the configuration that
the BIOS sets at boot by default.  That is device-dependent, however.

--- linux/drivers/char/keyboard.c.orig	2008-01-14 00:26:12.000000000 +0000
+++ linux/drivers/char/keyboard.c	2008-01-14 00:33:03.000000000 +0000
@@ -67,6 +67,9 @@
 
 #define KBD_DEFLOCK 0
 
+unsigned char default_leds = KBD_DEFLEDS;
+module_param(default_leds, byte, S_IRUGO | S_IWUSR);
+
 void compute_shiftstate(void);
 
 /*
@@ -1405,8 +1408,8 @@
 	int error;
 
         for (i = 0; i < MAX_NR_CONSOLES; i++) {
-		kbd_table[i].ledflagstate = KBD_DEFLEDS;
-		kbd_table[i].default_ledflagstate = KBD_DEFLEDS;
+		kbd_table[i].ledflagstate = default_leds;
+		kbd_table[i].default_ledflagstate = default_leds;
 		kbd_table[i].ledmode = LED_SHOW_FLAGS;
 		kbd_table[i].lockstate = KBD_DEFLOCK;
 		kbd_table[i].slockstate = 0;
--- linux/include/linux/kbd_kern.h.orig	2008-01-14 00:32:36.000000000 +0000
+++ linux/include/linux/kbd_kern.h	2008-01-14 00:32:48.000000000 +0000
@@ -13,6 +13,7 @@
 extern char func_buf[];
 extern char *funcbufptr;
 extern int funcbufsize, funcbufleft;
+extern unsigned char default_leds;
 
 /*
  * kbd->xxx contains the VC-local things (flag settings etc..)
--- linux/Documentation/kernel-parameters.txt.orig	2008-01-14 00:38:40.000000000 +0000
+++ linux/Documentation/kernel-parameters.txt	2008-01-14 00:41:21.000000000 +0000
@@ -550,6 +550,15 @@
 			Set system-wide default UTF-8 mode for all tty's.
 			Default is 0 and by setting to 1, it enables UTF-8
 			mode for all newly opened or allocated terminals.
+	
+	keyboard.default_leds=
+			[KEYBOARD]
+			Format=<ledmask>
+			Mask of the leds to activate on consoles by default.
+			ScrollLock: 1
+			NumLock: 2
+			CapsLock: 4
+			KanaLock: 8
 
 	dhash_entries=	[KNL]
 			Set number of hash buckets for dentry cache.

Re: [PATCH] Default keyboard LEDs

[Jan Engelhardt]

On Jan 14 2008 00:52, 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.

Apart from openvt being able to find the first unused tty,
what is openvt good for? (Read: I could just as well run
`bash </dev/tty8 >/dev/tty8 2>/dev/tty8`)

Re: [PATCH] Default keyboard LEDs

[Samuel Thibault]

Jan Engelhardt, le Mon 14 Jan 2008 02:40:08 +0100, a écrit :
> On Jan 14 2008 00:52, 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.
> 
> Apart from openvt being able to find the first unused tty,
> what is openvt good for? (Read: I could just as well run
> `bash </dev/tty8 >/dev/tty8 2>/dev/tty8`)

But it is a burden (you forgot '&' btw ;) ). Also, openvt properly sets
the controlling tty, can run a login shell, etc...

Anyway, be it openvt or bash, the LED issue exists :)

Samuel

Re: [PATCH] Default keyboard LEDs

[H. Peter Anvin]

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 <samuel.thibault@ens-lyon.org>
> 
> 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:

--------K-M00400017--------------------------
MEM 0040h:0017h - KEYBOARD - STATUS FLAGS 1
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.

	-hpa

Re: [PATCH] Default keyboard LEDs

[Samuel Thibault]

H. Peter Anvin, le Sun 13 Jan 2008 19:50:34 -0800, a écrit :
> >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:

I should have said "arch-dependent".
I didn't mean it wasn't possible, but just it'd probably be better that
driver experts do it, not me :)

> --------K-M00400017--------------------------
> MEM 0040h:0017h - KEYBOARD - STATUS FLAGS 1
> 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.

Samuel