Hello! Mark H Weaver <m...@netris.org> skribis:
> Here's a preliminary patch to add support for hibernation. To enable > it, you'll also need to add a line like this to your 'operating-system' > definition. > > (kernel-arguments '("resume=/dev/sda2")) > > Where the device named is a swap partition. Awesome! I missed this. > It may be that we should add a dedicated 'resume-device' field to the > 'operating-system'. Thoughts? I think it’s OK this way (though we should give an example in the manual), but not strong opinion. > From ad1d583eb6f009a2dfbc284cb8368608caf27a05 Mon Sep 17 00:00:00 2001 > From: Mark H Weaver <m...@netris.org> > Date: Sun, 14 Aug 2016 05:33:12 -0400 > Subject: [PATCH] PRELIMINARY: Add support for hibernation. > > * gnu/build/linux-boot.scm (boot-system): Look for a resume=<device-name> > argument on the linux command line, and if present, attempt to resume from > hibernation. > * gnu/services/desktop.scm (<elogind-configuration>): Change the default > value of the 'handle-hibernate-key' key to 'hibernate'. [...] > + (resume-device (find-long-option "resume" args))) Could you mention this argument under “Initial RAM Disk”? > + ;; > + ;; Attempt to resume from hibernation. > + ;; > + ;; IMPORTANT: This *must* happen before we mount any filesystems on > + ;; disk. Quoting linux-libre/Documentation/swsusp.txt: > + ;; > + ;; * BIG FAT WARNING > ************************************************** > + ;; * > + ;; * If you touch anything on disk between suspend and resume... > + ;; * ...kiss your data goodbye. > + ;; * > + ;; * If you do resume from initrd after your filesystems are > mounted... > + ;; * ...bye bye root partition. > + ;; * [this is actually same case as above] > + ;; * > + (when (and resume-device > + (file-exists? resume-device) > + (file-exists? "/sys/power/resume")) > + (false-if-exception > + (let* ((device-base-name > + ;; The base name of the device file, after resolving > + ;; symlinks. > + (let loop ((file resume-device)) > + (match (stat:type (lstat file)) > + ('symlink > + (let ((target (readlink file))) > + (if (string-prefix? "/" target) > + (loop target) > + (loop (string-append (dirname file) "/" > target))))) > + (_ (basename file))))) > + (major+minor > + ;; The major:minor string (e.g. "8:2") corresponding > + ;; to the resume device. > + (call-with-input-file (string-append "/sys/class/block/" > + device-base-name > + "/dev") > + read-line))) > + ;; Write the major:minor string to /sys/power/resume > + ;; to attempt resume from hibernation. > + (when major+minor > + (call-with-output-file "/sys/power/resume" > + (cut display major+minor <>)))))) Could you turn the (false-if-exception …) expression into a separate procedure? I would perhaps remove ‘false-if-exception’: that way, if something goes wrong, we’ll be able to see what the error is and get a REPL. It might also be useful to display a message like “resuming from device /dev/xyz (8:2)…” Apart from that it seems alright! It’d be interesting to see if we can write a test. The existing tests do not use a swap partition, but adding one shouldn’t be too hard. Thank you, Ludo’.