[ltp] Battery drain in S3

[Nathan Kurz]

On Thu, Dec 09, 2004 at 02:15:55PM +0100, Joachim Schrod wrote:
> Many people report that resume from suspend-to-RAM doesn't work any
> more with 2.6 kernels. Supposedly, it leaves the screen blank, with no
> way to revitalize the system.
> 
> Some report that one needs to unload PCMCIA for suspend. Some report
> that proper working might depend on the graphics chip. I don't have a
> spare disk handy, otherwise I would make a test installation. Maybe I
> can re-install my old T21 and test it there.

I think I can confirm that on an X30 (with i830 video) that the blank
screen on APM suspend to ram resume is not PCMCIA related.  While
narrowing down the problem, I got the hang you describe even when
running from a text console in single user mode with all the modules I
could remove (including PCMCIA support) removed.  Interestingly, if
from this state I did a BIOS suspend to disk immediately followed by a
suspend to ram, the hang was less likely to occur.

My personal pet theory is that the hang is a failure to properly
reinitialize the video card on resume, and thus is parallel to the
problem in ACPI that requires the acpi_sleep=s3_bios boot option.  I'd
like to see what happens if one were to take the video
reinitialization code this option performs and to port it to APM, but
the relevant sections are in assembler and I'm not up to the task.  

--nate