Session Leader: bwidawsk
hackmd (content has been migrated to this page)
Previous Generation
S1
S2
- S3
- S4 - useful as BIOS reinits all hardware on resume
Opportunistic Idle (Runtime PM)
- power down USB devices, SATA, etc?
- We can switch PCI devices without drivers to D3, but this is disabled by default (hw.pci.do_power_nodriver=0) as it breaks things
Next Generation
- Intel's Low Power Idle (s0i1, s0i3 - aka s0ix)
- Some systems going forward just don't support S3
- S3 Emulation (Linux "suspend to idle")
- Opportunistic Idle
https://www.uefi.org/sites/default/files/resources/Intel_ACPI_Low_Power_S0_Idle.pdf
turbostat is in ports, replacement for powertop
Known S3 Issues
- LCD on various laptops (often KMS fixes this)
- nvidia(4)
- em(4) on some systems does not survive resume (Thinkpad X220)
- Some Samsung nvd(4) drives will need nvme(4) code to suspend/resume successfully
- Some devices have broken timecounters on resume (either frozen, or racing)
- S4 may be useful as a base suspend/resume when S3 doesn't work