* Sebastian Leske [Mon Nov 29, 2010 at 01:38:21 +0100]: > I got bitten by this bug as well, similarly to Michael Conner above: > I installed uswsusp to be able to hibernate/resume. > s2disk worked flawlessly, but on booting the system simply did not > bother to resume, booting normally instead.
> My analysis: > After digging through the initramfs scripts, I discovered that this is > because on booting resume is only triggered if $resume is set. > As far as I understand, the initramfs takes $resume from the kernel > command line (if set), and from /etc/initramfs-tools/conf.d/resume > otherwise. > In my case /etc/initramfs-tools/conf.d/resume did not exist. > It should have been created by the preinst of initramfs-tools; however > the preinst ( /var/lib/dpkg/info/initramfs-tools.preinst ) uses vol_id: [...] > This will always fail, because vol_id is no longer part of Debian (it was > removed from udev for version 146-1, see > /usr/share/doc/udev/changelog.Debian.gz ). This is no longer true for current versions of initramfs-tools, JFYI. > In summary: > * Resume from hibernation will only work if /etc/initramfs-tools/conf.d/resume > sets RESUME > * However, there is no (working) code to write > /etc/initramfs-tools/conf.d/resume, and no documentation explaining that it > needs to be set manually to make resume work > Thus, resume will probably fail to work in most cases. > I believe there are actually several bugs here: > 1) The code in the preinst of initramfs-tools to detect the swap partition > does > not work, because it uses vol_id. Fixed nowadays. > 2) Even if 1) were fixed, there may be cases where the swap partition is > incorrectly detected at installation time, or later changes. So fixing > preinst is not enough. > I agree with bug submitter jidanni that the swap partition should be > detected > when building the initramfs, not during preinst. > 3) Additionally, I don't quite understand why uswsusp refuses to resume if > $resume is not set (in > /usr/share/initramfs-tools/scripts/local-premount/uswsusp ). > The script does not actually use the value of $resume, it just aborts if > it is not set :-(. > I guess this could be considered a bug in uswsusp; I can report it against > uswsusp if discussion of this bug indicates that this makes sense. > To fix this, I would propose the following: > * Drop the code in initramfs-tools.preinst which tries to write RESUME to > /etc/initramfs-tools/conf.d/resume , which does not work anyway. Sounds reasonable too me. maximilian, what do you think of it? > * Document (e.g. in /usr/share/doc/initramfs-tools/README.Debian ) that > /etc/initramfs-tools/conf.d/resume can be used to set the resume device. > * When building the initramfs, use the value from > /etc/initramfs-tools/conf.d/resume > if it exists; otherwise try to find it yourself: > - if /etc/uswsusp.conf exists, it probably makes sense to read it ("resume > device =") > - otherwise grab the current swap device (the "config" script from uswsusp > already has code for that) > This is still problematic if there is >1 swap device. Even better probably > would be to use debconf to prompt for the resume device, if this is > practical... > I am willing to help implement / test this, but first I'll wait for some > feedback if I'm even on the right track :-). Sorry that no one seemed to care about it for so long. What could be a proper way to resolve that nowadays, taking uswsusp, hibernate,... into account? dracut has some code in modules.d/95resume/. IMHO we should find a way which avoids duplicated code. Related bug reports: http://bugs.debian.org/574653 https://bugs.launchpad.net/ubuntu/+source/initramfs-tools/+bug/50437 regards, -mika-
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