ACPI seems to work, but sleep states don't

ACPI seems to work, but sleep states don't

[Johannes Wilms]

Hi,

I am experiencing strange results with ACPI on my Fujitsu-Siemens Amilo
M7400 (Centrino 1.4GHz), Debian Sarge, Kernel 2.6.11, with some patches
for Winbond SD/MMC card support.

I have ACPI support including Sleep States compiled into the kernel, and
 the Debian packages acpi and acpid installed to access the functions.
The /proc/acpi interface seems to work nicely, returning all information
(like battery status or button events) correctly. Also cat
/sys/power/states lists "standby mem disk" as it should.

On the web, several people report that also sleep states work. I have
appended a list of URLs of reports I have discovered. They all report
that at least disk = Hibernate = S4 works out of the box. They all use
slightly different 2.6 kernels, but rather older ones than mine.

For me, however, echo disk > /sys/power/state doesn't seem to do
anything at all. echo standby > /sys/power/state makes the screen go
black for a second or so, and then return to normal again, and produces
in dmesg:
PM: Preparing system for suspend
Stopping tasks: ===== ... ======|
Restarting tasks... done
The only thing which seems to be the same as in the other installations
is echo mem > /sys/power/state, which does seem to put the system in
suspend mode, but the display cannot be activated again.

I am not particularly interested in the S3 suspend mode, but it would be
nice if I could use S4 and standby.

Maybe I should mention that acpid gives the error message
"acpid: can't open /proc/acpi/event: Device or resource busy"
but then I don't think that's related really.

I would appreciate your help on how to get S4 and standby working, as I
am out of ideas. Especially, I cannot find any reports of a similar
situation online.

Thank you very much,
Johannes Wilms


Other Amilo M7400 users:
http://www.angelfire.com/linux/notebook/fujitsu/m7400.html
http://www.cc.jyu.fi/~hastrup/linux/amilo.html
http://www.rage-star.org/linux.html
http://www.david-froehlich.de/index.html?computer-amilo.html


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