Bug#725284: Bug#779412: block devices loosing state after resume: trigger udev rules to re-apply settings
Am 28.02.2015 um 09:30 schrieb Chris: A draft for such a central systemd unit file: [Unit] Description=Trigger all block device udev rules on resume, to re-apply all non-permanent device settings (e.g. smartctl and hdparm rules). After=suspend.target After=hibernate.target After=hybrid-sleep.target This does not work. Ordering After=foo.target does *not* guarantee that the service is run on resume. I already mentioned that, when a similar file was added to anacron [1]. Unfortunately it was applied anyway and now this file is copied over and over again and posted to various bug reports. Michael [1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=744753#124 -- Why is it that all of the instruments seeking intelligent life in the universe are pointed away from Earth? signature.asc Description: OpenPGP digital signature
Bug#725284: Bug#779412: block devices loosing state after resume: trigger udev rules to re-apply settings
Am 28.02.2015 um 09:30 schrieb Chris: (http://bugs.debian.org/779412 explanation) There is a general problem with non-permanent block devices settings (hard disks, optical disks, usb storage, ...), that are not restored when resuming from suspend (instead using factory defaults and loosing all pre-suspend settings). And as long as the ata/scsi command set drivers can not save and restore every state register a device may have (impossible?), systemd may ship a viable workaround for this: A systemd unit file could trigger an udev change action upon resume for block devices. This way the same udev rules that set up the devices when they are first plugged, will re-apply their settings after resume. Providing this centrally with the systemd package could avoid that multiple packages ship their own files, resulting in multiple change events triggerd on each resume. Examples for very important (non-permanent) settings are with hdparm (i.e. the important -B hard disk wear settings) https://bugs.debian.org/725284 smartctl/mdadm/lvm/btrfs/zfs/... (i.e. set error recovery timeouts to prevent controller resets and data loss) http://sourceforge.net/p/smartmontools/mailman/message/33501936/ I don't think working around this in udev/systemd is a good idea. After all, most of those custom settings aren't applied via udev rules anyway. This should be fixed in the kernel properly (or the individual services) and not be papered over in systemd. Marco, what do you think? -- Why is it that all of the instruments seeking intelligent life in the universe are pointed away from Earth? signature.asc Description: OpenPGP digital signature
Bug#725284: Bug#779412: block devices loosing state after resume: trigger udev rules to re-apply settings
Am Sat, 28 Feb 2015 09:38:27 +0100 schrieb Michael Biebl bi...@debian.org: I don't think working around this in udev/systemd is a good idea. Idealy and in the long run, the kernel drivers should keep state, yes. But until then, better not to make releases with default configurations that deliver serious problems (excessive hardware wear, data loss) to the users. I believe before things stadardized around systemd and udev, packages like hdparm, laptop-mode-tools, pm-utils, acpi-support, gnome-power-manager, and more, all tried to work around problems with block devices loosing state. Unfortunately, accumulating a large mess and interferences resuling in releases with many bugs in this regard. Now the situation can improve a lot, if we can say packages are safe if they use udev rules to initialize devices. (As the kernel keeps state, or systemd centrally triggers a udev change event where this is not (yet) the case.) most of those custom settings aren't applied via udev rules anyway. Which settings were you refering to? With current versions hdparm, mdadm, etc. all seem to ship udev rules. And that seems to be the proper way to configure the standard hot-pluggable systems of today. (leaving aside embedded, non-systemd, non udev systems) -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
