Qualche nota dopo il post sul tema. La prima è che se c’è qualche processo in uno stato di “Uninterruptible sleep” (quello che è indicato come D da ps) la sospensione non funziona, ameno per me, il che mi sembra ragionevole anche se è una seccatura. Spesso si tratta di processi che hanno problemi con l’accesso all’hardware (a me succede con la scheda ISDN, dato che il modulo del kernel è un po’ raffazzonato, e a volte con il masterizzatore se il DVD è rovinato).
La seconda è che compilando il kernel 2.6.23 con make oldconfig, la parte “Hibernation aka suspend to disk” e “suspend to ram” mi sono comparse come nuove (mah!) e ne ho approfittato per vedere l’help di suspend to disk dice:
You can suspend your machine with ‘echo disk > /sys/power/state’. Alternatively, you can use the additional userland tools available from <http://suspend.sf.net>.
In principle it does not require ACPI or APM, although for example ACPI will be used for the final steps when it is available. One of the reasons to use software suspend is that the firmware hooks for suspend states like suspend-to-RAM (STR) often don’t work very well with Linux.
It creates an image which is saved in your active swap. Upon the next boot, pass the ‘resume=/dev/swappartition’ argument to the kernel to have it detect the saved image, restore memory state from it, and continue to run as before. If you do not want the previous state to be reloaded, then use the ‘noresume’ kernel command line argument. Note, however, that fsck will be run on your filesystems and you will need to run mkswap against the swap partition used for the suspend.
It also works with swap files to a limited extent (for details see <file:Documentation/power/swsusp-and-swap-files.txt>).
Right now you may boot without resuming and resume later but in the meantime you cannot use the swap partition(s)/file(s) involved in
suspending. Also in this case you must not use the filesystems that were mounted before the suspend. In particular, you MUST NOT
MOUNT any journaled filesystems mounted before the suspend or they will get corrupted in a nasty way.
For more information take a look at <file:Documentation/power/swsusp.txt>.
