OMAP3: PM : Timer to turn LCD off

OMAP3: PM : Timer to turn LCD off

[Premi, Sanjeev]

While testing cpuidle (from Kevin's PM beanch) with default configuration for OMAP3EVM, the c-state never transitions from C0.

Even compiling with minimal drivers did not help. "fck_core1" continues to be active.
Also, the LCD continues to be powered on... Despite compiling out V4L and FB drivers.

A simple way to turn LCD off would be to implement an inactivity timer. (e.g. serial.c on the pm branch)

The question is - where should this timer be implemented?
- As part of the backlight driver?
  OR
- As part of the fb driver?
  OR
- Should it be tied to the board initialization?

Best regards,
Sanjeev

Re: OMAP3: PM : Timer to turn LCD off

[Imre Deak]

On Fri, Feb 20, 2009 at 02:24:50PM +0100, ext Premi, Sanjeev wrote:
> While testing cpuidle (from Kevin's PM beanch) with default configuration for OMAP3EVM, the c-state never transitions from C0.
> 
> Even compiling with minimal drivers did not help. "fck_core1" continues to be active.
> Also, the LCD continues to be powered on... Despite compiling out V4L and FB drivers.
> 
> A simple way to turn LCD off would be to implement an inactivity timer. (e.g. serial.c on the pm branch)

Blanking seems to me more of a user space policy. You could turn off the
LCD backlight from the board file if the FB driver is not configured.

--Imre

> 
> The question is - where should this timer be implemented?
> - As part of the backlight driver?
>   OR
> - As part of the fb driver?
>   OR
> - Should it be tied to the board initialization?
> 
> Best regards,
> Sanjeev
> --
> To unsubscribe from this list: send the line "unsubscribe linux-omap" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html