Bao, Zheng wrote:
I have _S4 in my dsdt.asl. But the dmesg only reports:
ACPI: (supports S0 S1 S2 S3 S5)
And cat /sys/power/state only says:
Standby mem
S4 is not used for suspend to disk in Linux AFAIK. You just need to compile in suspend to disk support and specify a resume partition on the kernel command line (Usually your swap partition).