Message-ID: <20070704214047.GB1836@elf.ucw.cz>
Date:	Wed, 4 Jul 2007 23:40:47 +0200
From:	Pavel Machek <pavel@....cz>
To:	Dmitry Torokhov <dtor@...ightbb.com>
Cc:	Andi Kleen <ak@...e.de>, Indan Zupancic <indan@....nu>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Stephen Hemminger <shemminger@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, bwalle@...e.de
Subject: Re: blink driver power saving

Hi!

> > > > > Perhaps one of you geniuses who all hate it can find a better way to
> > > > > solve the "video output dead after kexec; but need visual feedback to the user
> > > > > while crash dumping" problem. I'm waiting for your patches.
> > > > >
> > > > 
> > > > I don't don't like it ;) Unfortunately too many people end up enabling
> > > 
> > > Yes that's pretty weird. I admit I hadn't expected
> > > that problem. blink is equivalent to "annoy me" and it
> > > is a mystery why so many people should willingly ask their computer to 
> > > annoy them.
> > 
> > tristate "Keyboard blink driver"
> > 
> > ...drivers are not expected to act on their own. I was expecting to
> > get nice /sys/class/led* interface to my keyboard leds.
> > 
> > BTW ... I still believe we should have /sys/class/led* interface to
> > those leds. I'd like to make them blink with hdd activity on some
> > machines... of course, that needs non-buggy KBC.
> 
> I'll take patches. Ofcourse we'll have to keep the current EV_LED interface
> for compatibility.

It was simpler then I thought... but it has one small problem. It does
not actually work :-(..

it reaches the 

        printk("Setting led to %d\n", blinker->state);
        input_inject_event(&blinker->handle, EV_LED, LED_NUML, blinker->state);

code, but my numlock led does not actually change. Any ideas?
									Pavel

(leds-input.c:)

/*
 * LED <-> input subsystem glue
 *
 * Copyright 2007 Pavel Machek <pavel@...e.cz>
 * Copyright 2007 Dmitry Torokhov
 * Copyright 2005-2006 Openedhand Ltd.
 *
 * Author: Pavel Machek <pavel@...e.cz>
 * Based on code by: Richard Purdie <rpurdie@...nedhand.com>
 * 		     
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/leds.h>

#include <linux/module.h>
#include <linux/input.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <linux/init.h>

struct blinker {
	struct delayed_work work;
	struct input_handle handle;
	int state;
};

struct blinker *blinker;

static void inputled_set(struct led_classdev *led_cdev, enum led_brightness value)
{
	blinker->state = value;
	schedule_delayed_work(&blinker->work, 0);
}

static struct led_classdev input_led = {
	.name			= "input",
	.default_trigger	= "sharpsl-charge",
	.brightness_set		= inputled_set,
};

static void blink_task_handler(struct work_struct *work)
{
	struct blinker *blinker = container_of(work, struct blinker, work.work);
	printk("Setting led to %d\n", blinker->state);
	input_inject_event(&blinker->handle, EV_LED, LED_NUML, blinker->state);
}

static void blink_event(struct input_handle *handle, unsigned int type,
		        unsigned int code, int down)
{
	/*
	 * This is a very rare handler that does not process any input
	 * events; just injects them.
	 */
}

static int blink_connect(struct input_handler *handler, struct input_dev *dev,
			  const struct input_device_id *id)
{
	struct input_handle *handle;
	int error;

	blinker = kzalloc(sizeof(struct blinker), GFP_KERNEL);
	if (!blinker)
		return -ENOMEM;

	INIT_DELAYED_WORK(&blinker->work, blink_task_handler);

	handle = &blinker->handle;
	handle->dev = dev;
	handle->handler = handler;
	handle->name = "blink";
	handle->private = blinker;

	error = input_register_handle(handle);
	if (error)
		goto err_free_handle;

	error = input_open_device(handle);
	if (error)
		goto err_unregister_handle;

	error = led_classdev_register(NULL, &input_led);
	if (error < 0)
		goto err_input_close_device;

	return 0;

 err_input_close_device:
	input_close_device(handle);
 err_unregister_handle:
	input_unregister_handle(handle);
 err_free_handle:
	kfree(handle);
	return error;
}

static void blink_disconnect(struct input_handle *handle)
{
	struct blinker *blinker = handle->private;

	led_classdev_unregister(&input_led);
	cancel_rearming_delayed_work(&blinker->work);
	input_close_device(handle);
	input_unregister_handle(handle);
	kfree(blinker);
}

static const struct input_device_id blink_ids[] = {
	{
		.flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_LEDBIT,
		.evbit = { BIT(EV_LED) },
		.ledbit = { [LONG(LED_NUML)] = BIT(LED_NUML) },
	},
	{ }
};

static struct input_handler blink_handler = {
	.event		= blink_event,
	.connect	= blink_connect,
	.disconnect	= blink_disconnect,
	.name		= "blink",
	.id_table	= blink_ids,
};

static int __init blink_handler_init(void)
{
	return input_register_handler(&blink_handler);
}

static void __exit blink_handler_exit(void)
{
	input_unregister_handler(&blink_handler);
	flush_scheduled_work();
}

module_init(blink_handler_init);
module_exit(blink_handler_exit);




-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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