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| -rw-r--r-- | Documentation/power/devices.txt | 90 |
1 files changed, 0 insertions, 90 deletions
diff --git a/Documentation/power/devices.txt b/Documentation/power/devices.txt index f987afe..fba1e05 100644 --- a/Documentation/power/devices.txt +++ b/Documentation/power/devices.txt @@ -135,96 +135,6 @@ HW. FREEZE -- stop DMA and interrupts, and be prepared to reinit HW from scratch. That probably means stop accepting upstream requests, the -actual policy of what to do with them beeing specific to a given -driver. It's acceptable for a network driver to just drop packets -while a block driver is expected to block the queue so no request is -lost. (Use IDE as an example on how to do that). FREEZE requires no -power state change, and it's expected for drivers to be able to -quickly transition back to operating state. - -SUSPEND -- like FREEZE, but also put hardware into low-power state. If -there's need to distinguish several levels of sleep, additional flag -is probably best way to do that. - -Transitions are only from a resumed state to a suspended state, never -between 2 suspended states. (ON -> FREEZE or ON -> SUSPEND can happen, -FREEZE -> SUSPEND or SUSPEND -> FREEZE can not). - -All events are: - -[NOTE NOTE NOTE: If you are driver author, you should not care; you -should only look at event, and ignore flags.] - -#Prepare for suspend -- userland is still running but we are going to -#enter suspend state. This gives drivers chance to load firmware from -#disk and store it in memory, or do other activities taht require -#operating userland, ability to kmalloc GFP_KERNEL, etc... All of these -#are forbiden once the suspend dance is started.. event = ON, flags = -#PREPARE_TO_SUSPEND - -Apm standby -- prepare for APM event. Quiesce devices to make life -easier for APM BIOS. event = FREEZE, flags = APM_STANDBY - -Apm suspend -- same as APM_STANDBY, but it we should probably avoid -spinning down disks. event = FREEZE, flags = APM_SUSPEND - -System halt, reboot -- quiesce devices to make life easier for BIOS. event -= FREEZE, flags = SYSTEM_HALT or SYSTEM_REBOOT - -System shutdown -- at least disks need to be spun down, or data may be -lost. Quiesce devices, just to make life easier for BIOS. event = -FREEZE, flags = SYSTEM_SHUTDOWN - -Kexec -- turn off DMAs and put hardware into some state where new -kernel can take over. event = FREEZE, flags = KEXEC - -Powerdown at end of swsusp -- very similar to SYSTEM_SHUTDOWN, except wake -may need to be enabled on some devices. This actually has at least 3 -subtypes, system can reboot, enter S4 and enter S5 at the end of -swsusp. event = FREEZE, flags = SWSUSP and one of SYSTEM_REBOOT, -SYSTEM_SHUTDOWN, SYSTEM_S4 - -Suspend to ram -- put devices into low power state. event = SUSPEND, -flags = SUSPEND_TO_RAM - -Freeze for swsusp snapshot -- stop DMA and interrupts. No need to put -devices into low power mode, but you must be able to reinitialize -device from scratch in resume method. This has two flavors, its done -once on suspending kernel, once on resuming kernel. event = FREEZE, -flags = DURING_SUSPEND or DURING_RESUME - -Device detach requested from /sys -- deinitialize device; proably same as -SYSTEM_SHUTDOWN, I do not understand this one too much. probably event -= FREEZE, flags = DEV_DETACH. - -#These are not really events sent: -# -#System fully on -- device is working normally; this is probably never -#passed to suspend() method... event = ON, flags = 0 -# -#Ready after resume -- userland is now running, again. Time to free any -#memory you ate during prepare to suspend... event = ON, flags = -#READY_AFTER_RESUME -# - - -pm_message_t meaning - -pm_message_t has two fields. event ("major"), and flags. If driver -does not know event code, it aborts the request, returning error. Some -drivers may need to deal with special cases based on the actual type -of suspend operation being done at the system level. This is why -there are flags. - -Event codes are: - -ON -- no need to do anything except special cases like broken -HW. - -# NOTIFICATION -- pretty much same as ON? - -FREEZE -- stop DMA and interrupts, and be prepared to reinit HW from -scratch. That probably means stop accepting upstream requests, the actual policy of what to do with them being specific to a given driver. It's acceptable for a network driver to just drop packets while a block driver is expected to block the queue so no request is |
