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A wealth of suspend options
Patrick Mochel has posted a new set of power
management patches. Power management is, of course, one of the last
unfinished projects in the 2.6.0-test kernel. So developments in that area
are of interest.
Much energy has gone into the suspend-to-disk implementation. Patrick has been unable to come to an understanding with (2.6) swsusp maintainer Pavel Machek; rather than keep trying, he has chosen to create his own implementation (starting with swsusp) called "pmdisk." Should Linus accept the patches, the 2.6.0-test kernel will have two separate, competing implementations of the suspend-to-disk functionality. The swsusp version has been reverted to its previous state; the patch includes the comment "Note that I would never publically admit to putting such code into the kernel." The new pmdisk implementation has since seen some fixes, though it still does not work on SMP systems, and apparently will not for some time. There is a /sys/power/state file used to control pmdisk; writing "disk" to that file will cause the system to suspend itself to disk. Beyond that, pmdisk is still mostly the swsusp implementation with a lot of cleanup work and the names of the functions and variables changed. One remaining question with the suspend-to-disk functionality is what will happen to all of Nigel Cunningham's work. Nigel has put a great deal of effort into the 2.4 swsusp implementation, with the result that it has become a reliable option for many users; see our review of that work from August. Nigel would like to port his work forward to 2.6, but is uncertain about what to port to. This whole situation could be resolved by Linus, who has not yet accepted the "fork swsusp" patch. Releasing a 2.6.0 kernel with two different suspend implementations seems like a suboptimal course which could reflect poorly on the Linux development process. Linus has made no public noises to this effect, but it would not be surprising if he imposed some sort of solution that led to a single suspend subsystem in 2.6.0. (Log in to post comments)
A wealth of suspend options Posted Sep 12, 2003 9:40 UTC (Fri) by hansl (subscriber, #5086) [Link] Funny, just noticed that both authors' intials are PM,and that Patrick Mochel and Pavel Machek now maintain their own version of Power Management (PM) code. -Hans
A wealth of suspend options Posted Sep 12, 2003 16:54 UTC (Fri) by cpeterso (guest, #305) [Link] Maybe PM and PM are the same person! :-)
A wealth of suspend options Posted Sep 19, 2003 7:11 UTC (Fri) by turpie (guest, #5219) [Link] That would be an interesting way to try some more experimental ideas as you could just blame them on the other identity if they don't work out.
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