diff options
Diffstat (limited to 'Documentation/power')
| -rw-r--r-- | Documentation/power/pci.txt | 38 | ||||
| -rw-r--r-- | Documentation/power/swsusp.txt | 83 | ||||
| -rw-r--r-- | Documentation/power/video.txt | 3 | ||||
| -rw-r--r-- | Documentation/power/video_extension.txt | 19 |
4 files changed, 133 insertions, 10 deletions
diff --git a/Documentation/power/pci.txt b/Documentation/power/pci.txt index 35b1a7dae342..6fc9d511fc39 100644 --- a/Documentation/power/pci.txt +++ b/Documentation/power/pci.txt @@ -291,6 +291,44 @@ a request to enable wake events from D3, two calls should be made to pci_enable_wake (one for both D3hot and D3cold). +A reference implementation +------------------------- +.suspend() +{ + /* driver specific operations */ + + /* Disable IRQ */ + free_irq(); + /* If using MSI */ + pci_disable_msi(); + + pci_save_state(); + pci_enable_wake(); + /* Disable IO/bus master/irq router */ + pci_disable_device(); + pci_set_power_state(pci_choose_state()); +} + +.resume() +{ + pci_set_power_state(PCI_D0); + pci_restore_state(); + /* device's irq possibly is changed, driver should take care */ + pci_enable_device(); + pci_set_master(); + + /* if using MSI, device's vector possibly is changed */ + pci_enable_msi(); + + request_irq(); + /* driver specific operations; */ +} + +This is a typical implementation. Drivers can slightly change the order +of the operations in the implementation, ignore some operations or add +more deriver specific operations in it, but drivers should do something like +this on the whole. + 5. Resources ~~~~~~~~~~~~ diff --git a/Documentation/power/swsusp.txt b/Documentation/power/swsusp.txt index 4e1627cc5b51..7a6b78966459 100644 --- a/Documentation/power/swsusp.txt +++ b/Documentation/power/swsusp.txt @@ -164,10 +164,11 @@ place where the thread is safe to be frozen (no kernel semaphores should be held at that point and it must be safe to sleep there), and add: - try_to_freeze(); + try_to_freeze(); If the thread is needed for writing the image to storage, you should -instead set the PF_NOFREEZE process flag when creating the thread. +instead set the PF_NOFREEZE process flag when creating the thread (and +be very carefull). Q: What is the difference between between "platform", "shutdown" and @@ -232,3 +233,81 @@ A: Try running cat `cat /proc/[0-9]*/maps | grep / | sed 's:.* /:/:' | sort -u` > /dev/null after resume. swapoff -a; swapon -a may also be usefull. + +Q: What happens to devices during swsusp? They seem to be resumed +during system suspend? + +A: That's correct. We need to resume them if we want to write image to +disk. Whole sequence goes like + + Suspend part + ~~~~~~~~~~~~ + running system, user asks for suspend-to-disk + + user processes are stopped + + suspend(PMSG_FREEZE): devices are frozen so that they don't interfere + with state snapshot + + state snapshot: copy of whole used memory is taken with interrupts disabled + + resume(): devices are woken up so that we can write image to swap + + write image to swap + + suspend(PMSG_SUSPEND): suspend devices so that we can power off + + turn the power off + + Resume part + ~~~~~~~~~~~ + (is actually pretty similar) + + running system, user asks for suspend-to-disk + + user processes are stopped (in common case there are none, but with resume-from-initrd, noone knows) + + read image from disk + + suspend(PMSG_FREEZE): devices are frozen so that they don't interfere + with image restoration + + image restoration: rewrite memory with image + + resume(): devices are woken up so that system can continue + + thaw all user processes + +Q: What is this 'Encrypt suspend image' for? + +A: First of all: it is not a replacement for dm-crypt encrypted swap. +It cannot protect your computer while it is suspended. Instead it does +protect from leaking sensitive data after resume from suspend. + +Think of the following: you suspend while an application is running +that keeps sensitive data in memory. The application itself prevents +the data from being swapped out. Suspend, however, must write these +data to swap to be able to resume later on. Without suspend encryption +your sensitive data are then stored in plaintext on disk. This means +that after resume your sensitive data are accessible to all +applications having direct access to the swap device which was used +for suspend. If you don't need swap after resume these data can remain +on disk virtually forever. Thus it can happen that your system gets +broken in weeks later and sensitive data which you thought were +encrypted and protected are retrieved and stolen from the swap device. +To prevent this situation you should use 'Encrypt suspend image'. + +During suspend a temporary key is created and this key is used to +encrypt the data written to disk. When, during resume, the data was +read back into memory the temporary key is destroyed which simply +means that all data written to disk during suspend are then +inaccessible so they can't be stolen later on. The only thing that +you must then take care of is that you call 'mkswap' for the swap +partition used for suspend as early as possible during regular +boot. This asserts that any temporary key from an oopsed suspend or +from a failed or aborted resume is erased from the swap device. + +As a rule of thumb use encrypted swap to protect your data while your +system is shut down or suspended. Additionally use the encrypted +suspend image to prevent sensitive data from being stolen after +resume. diff --git a/Documentation/power/video.txt b/Documentation/power/video.txt index 68734355d7cf..881a37e3eeb0 100644 --- a/Documentation/power/video.txt +++ b/Documentation/power/video.txt @@ -83,8 +83,10 @@ Compaq Armada E500 - P3-700 none (1) (S1 also works OK) Compaq Evo N620c vga=normal, s3_bios (2) Dell 600m, ATI R250 Lf none (1), but needs xorg-x11-6.8.1.902-1 Dell D600, ATI RV250 vga=normal and X, or try vbestate (6) +Dell D610 vga=normal and X (possibly vbestate (6) too, but not tested) Dell Inspiron 4000 ??? (*) Dell Inspiron 500m ??? (*) +Dell Inspiron 510m ??? Dell Inspiron 600m ??? (*) Dell Inspiron 8200 ??? (*) Dell Inspiron 8500 ??? (*) @@ -123,6 +125,7 @@ Toshiba Satellite 4030CDT s3_mode (3) Toshiba Satellite 4080XCDT s3_mode (3) Toshiba Satellite 4090XCDT ??? (*) Toshiba Satellite P10-554 s3_bios,s3_mode (4)(****) +Toshiba M30 (2) xor X with nvidia driver using internal AGP Uniwill 244IIO ??? (*) diff --git a/Documentation/power/video_extension.txt b/Documentation/power/video_extension.txt index 8e33d7c82c49..b2f9b1598ac2 100644 --- a/Documentation/power/video_extension.txt +++ b/Documentation/power/video_extension.txt @@ -1,13 +1,16 @@ -This driver implement the ACPI Extensions For Display Adapters -for integrated graphics devices on motherboard, as specified in -ACPI 2.0 Specification, Appendix B, allowing to perform some basic -control like defining the video POST device, retrieving EDID information -or to setup a video output, etc. Note that this is an ref. implementation only. -It may or may not work for your integrated video device. +ACPI video extensions +~~~~~~~~~~~~~~~~~~~~~ + +This driver implement the ACPI Extensions For Display Adapters for +integrated graphics devices on motherboard, as specified in ACPI 2.0 +Specification, Appendix B, allowing to perform some basic control like +defining the video POST device, retrieving EDID information or to +setup a video output, etc. Note that this is an ref. implementation +only. It may or may not work for your integrated video device. Interfaces exposed to userland through /proc/acpi/video: -VGA/info : display the supported video bus device capability like ,Video ROM, CRT/LCD/TV. +VGA/info : display the supported video bus device capability like Video ROM, CRT/LCD/TV. VGA/ROM : Used to get a copy of the display devices' ROM data (up to 4k). VGA/POST_info : Used to determine what options are implemented. VGA/POST : Used to get/set POST device. @@ -15,7 +18,7 @@ VGA/DOS : Used to get/set ownership of output switching: Please refer ACPI spec B.4.1 _DOS VGA/CRT : CRT output VGA/LCD : LCD output -VGA/TV : TV output +VGA/TVO : TV output VGA/*/brightness : Used to get/set brightness of output device Notify event through /proc/acpi/event: |