Re: Console blanking: blank on demand

Pavel Machek (pavel@suse.cz)
Sat, 7 Jun 2003 22:45:23 +0200


Hi!

> > [I seen you did some changes to screen blanking...]
> >
> > For pretty long time this is in my tree. It is pretty important for
> > small machines where display takes as much power as rest of system...
> >
> > What about applying?
>
> - What key is it using?

Whatever you map it to, but to map it you need (one-line) loadkeys support.

> - Is there somewhere under Documentation/ where the key should be
> documented?

I guess right approach is add patch to loadkeys adding BlankNow key,
then adding it to some obscure place in default keymap.

> - whitespace looks suspect.

Well, whitespace is wrong in kbd_init() [it uses 8 spaces, not a
tab]. I reindented it in this version...

> - The timer is left running across rmmod.

I do not think keyboard.c can be unloaded. There's
input_register_handler but no input_unregister_handler.

Pavel

%patch
Index: linux/drivers/char/keyboard.c
===================================================================
--- linux.orig/drivers/char/keyboard.c 2003-06-01 20:12:16.000000000 +0200
+++ linux/drivers/char/keyboard.c 2003-06-07 22:14:22.000000000 +0200
@@ -20,6 +20,7 @@
* parts by Geert Uytterhoeven, May 1997
*
* 27-05-97: Added support for the Magic SysRq Key (Martin Mares)
+ * 29-07-97: Added blank console key (Pavel Machek)
* 30-07-98: Dead keys redone, aeb@cwi.nl.
* 21-08-02: Converted to input API, major cleanup. (Vojtech Pavlik)
*/
@@ -86,7 +87,8 @@
fn_show_state, fn_send_intr, fn_lastcons, fn_caps_toggle,\
fn_num, fn_hold, fn_scroll_forw, fn_scroll_back,\
fn_boot_it, fn_caps_on, fn_compose, fn_SAK,\
- fn_dec_console, fn_inc_console, fn_spawn_con, fn_bare_num
+ fn_dec_console, fn_inc_console, fn_spawn_con, fn_bare_num, \
+ fn_blank_now

typedef void (fn_handler_fn)(struct vc_data *vc, struct pt_regs *regs);
static fn_handler_fn FN_HANDLERS;
@@ -320,6 +322,25 @@
con_schedule_flip(tty);
}

+static void blank_now_do(unsigned long unused)
+{
+ do_poke_blanked_console = 0;
+ do_blank_screen(0);
+}
+
+static struct timer_list blank_now_timer;
+
+static void fn_blank_now(struct vc_data *vc, struct pt_regs *regs)
+{
+ /* You ask why we have our own timer here? Well, it is because
+ we do not want user's release of keys to unblank
+ immediately. Even if we correctly guessed what is press and
+ what is release, thinkpad's broken bios will turn on
+ backlight for us... <pavel@ucw.cz> */
+ blank_now_timer.expires = jiffies + HZ;
+ add_timer(&blank_now_timer);
+}
+
static void applkey(struct vc_data *vc, int key, char mode)
{
static char buf[] = { 0x1b, 'O', 0x00, 0x00 };
@@ -1215,15 +1258,18 @@
{
int i;

- kbd0.ledflagstate = kbd0.default_ledflagstate = KBD_DEFLEDS;
- kbd0.ledmode = LED_SHOW_FLAGS;
- kbd0.lockstate = KBD_DEFLOCK;
- kbd0.slockstate = 0;
- kbd0.modeflags = KBD_DEFMODE;
- kbd0.kbdmode = VC_XLATE;
+ init_timer(&blank_now_timer);
+ blank_now_timer.function = blank_now_do;
+
+ kbd0.ledflagstate = kbd0.default_ledflagstate = KBD_DEFLEDS;
+ kbd0.ledmode = LED_SHOW_FLAGS;
+ kbd0.lockstate = KBD_DEFLOCK;
+ kbd0.slockstate = 0;
+ kbd0.modeflags = KBD_DEFMODE;
+ kbd0.kbdmode = VC_XLATE;

- for (i = 0 ; i < MAX_NR_CONSOLES ; i++)
- kbd_table[i] = kbd0;
+ for (i = 0 ; i < MAX_NR_CONSOLES ; i++)
+ kbd_table[i] = kbd0;

input_register_handler(&kbd_handler);

%diffstat
keyboard.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++---------
1 files changed, 55 insertions(+), 9 deletions(-)

-- 
When do you have a heart between your knees?
[Johanka's followup: and *two* hearts?]
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