Subject: Re: ACPI suspend support.
To: Daniel Carosone <>
From: Kentaro A. Kurahone <>
List: tech-kern
Date: 01/27/2005 05:15:36
On Thu, Jan 27, 2005 at 04:01:34PM +1100, Daniel Carosone wrote:
> Another datapoint on my older latitude c600, just because I felt like
> trying it even though I didn't expect it to work.
> S1 seems to almost work, in that the laptop 'freezes' and the power
> light goes to a slow blink.  It does not switch off the display,
> however, so I'm looking at the frozen screen contents until I press
> the power button to resume - at which point the display and backlight
> power off as everything else comes on again. Switching VT's brings the
> display back, and everything is fine from then on, except for the
> esa(4) which has no powerhooks yet.

The lack of powermanagement code in esa should not matter here since
all S1 suspend does is halt the CPU.  Odd.
> S2 seems to have no effect at all.

AFAIK no one implements this mode, even if it's defined in spec.
> S3 seems to power everything except the backlight off (the LCD panel
> is off, but I get a bright white background).  Powering on again I see
> the previous screen contents for a fraction of a second before the
> machine reboots.
> Being in or out of the docking station doesn't seem to affect the
> above.
> It's great to see progress on this, thankyou and keep it up!

Thanks for the feedback. :)

Kentaro A. Kurahone
SIGUSR1 Research and Development