Re: How does rfkill work?

[Larry Finger <Larry.Finger@lwfinger.net>]

Johannes Berg wrote:
> On Thu, 2009-04-02 at 20:48 +0200, Johannes Berg wrote:
> 
> Could you try something for me?
> 
> In drivers/leds/led-triggers.c in led_trigger_show you have
> 
>         list_for_each_entry(trig, &trigger_list, next_trig) {
> +		printk(KERN_DEBUG "available trigger: %s\n", trig->name);
>                 if (led_cdev->trigger && !strcmp(led_cdev->trigger->name,
>                                                         trig->name))
>                         len += sprintf(buf+len, "[%s] ", trig->name);
>                 else
>                         len += sprintf(buf+len, "%s ", trig->name);
>         }
> 
> could you do the modification, with a kernel that has the TRIG_NAME_MAX
> set to 50, and see what it prints? I'm completely confused by this
> failure mode since the garbage you get is actually put into brackets, so
> it seems the strcmp() is returning 0 which seems odd.

Have I told you that I hate things that appear to be intermittent?

I added the printk, returned TRIG_NAME_MAX to 50, rebuilt and rebooted. This
time I got

~/wireless-testing> cat /sys/class/leds/b43legacy-phy0\:\:rad/trigger
none ide-disk ADP1-online BAT0-charging-or-full BAT0-charging BAT0-full phy0rx
phy0tx phy0assoc phy0radio [rfkill0]
~/wireless-testing> dmesg | grep available
available trigger: ide-disk
available trigger: ADP1-online
available trigger: BAT0-charging-or-full
available trigger: BAT0-charging
available trigger: BAT0-full
available trigger: phy0rx
available trigger: phy0tx
available trigger: phy0assoc
available trigger: phy0radio
available trigger: rfkill0

I'll leave the printk in place for the moment.

The name is being truncated by "#define BUS_ID_SIZE 20" in
include/linux/device.h. As changing that define would be pretty invasive, I plan
to use a shorter name when the LED is registered.

The bad news is that the set brightness callback routine is still not being
called even though I tried BUS_ID_SIZE of 30..

Till later,

Larry