linuxconsole-dev

power management

[James S. <jsi...@tr...>]

So far for power management I have:

Placed a pm_dev inside input_dev.

If the input_dev has a struct pm_dev we do the following.

Every time input_open is called pm_access is called.

When input_close is called and handle->open==0 I call pm_idle_dev

For input_unregister_device I call pm_unregister(dev->pm_dev);

I find pm_register_device too driver specific to make generic. 
The next problem is power management for that particular device via a
key/button. I like to power the device off/on and control the level of
power going to the device. For example the touchscreen I'm working on. It
would be nice to dim/brighten the frontlight. The question is how to
implement this fine grain control.

P.S
   serio->write can send only one char at a time? 

Re: power management

[Vojtech P. <vo...@su...>]

On Tue, Jun 19, 2001 at 02:30:02PM -0700, James Simmons wrote:

> So far for power management I have:
> 
> Placed a pm_dev inside input_dev.
> 
> If the input_dev has a struct pm_dev we do the following.
> 
> Every time input_open is called pm_access is called.
> 
> When input_close is called and handle->open==0 I call pm_idle_dev
> 
> For input_unregister_device I call pm_unregister(dev->pm_dev);
> 
> I find pm_register_device too driver specific to make generic. 
> The next problem is power management for that particular device via a
> key/button. I like to power the device off/on and control the level of
> power going to the device. For example the touchscreen I'm working on. It
> would be nice to dim/brighten the frontlight. The question is how to
> implement this fine grain control.

Hmmm, I'll have to take a closer look at how powermanagement is
implement in Linux.

> P.S
>    serio->write can send only one char at a time? 

Yes, it has been designed for low speed devices, where the overhead
doesn't matter. But there is not a problem with redesigning it.

-- 
Vojtech Pavlik
SuSE Labs

Re: power management

[James S. <jsi...@tr...>]

> Hmmm, I'll have to take a closer look at how powermanagement is
> implement in Linux.

I have some form of power management going. It compiles but I have to test
it tomorrow. I have to still implement a userland interface to send a
event to power down. I'm hooked on send a EV_KEY with the code being
KEY_SUSPEND or KEY_POWER. As for the touchscreen diming the light should
really be apart of the fbdev api. Especially since laptops have back and
front lights but no touchscreens usually.

> > P.S
> >    serio->write can send only one char at a time? 
> 
> Yes, it has been designed for low speed devices, where the overhead
> doesn't matter. But there is not a problem with redesigning it.

The problem I'm having is I have to create packets and send them to the
serial device. For example for the power LED on the ipaq you have to
create a led packet which is:

typedef struct {
        unsigned char OffOnBlink;       /* 0=off 1=on 2=Blink */
        unsigned char TotalTime;        /* Units of 5 seconds */
        unsigned char OnTime;           /* units of 100m/s */
        unsigned char OffTime;          /* units of 100m/s */
} LED_IN;