On Tue, Jul 10, 2018 at 02:51:33PM +0200, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > Commit 52cdbdd49853 (driver core: correct device's shutdown order) > introduced a regression by breaking device shutdown on some systems. > > Namely, the devices_kset_move_last() call in really_probe() added by > that commit is a mistake as it may cause parents to follow children > in the devices_kset list which then causes shutdown to fail. For > example, if a device has children before really_probe() is called > for it (which is not uncommon), that call will cause it to be > reordered after the children in the devices_kset list and the > ordering of that list will not reflect the correct device shutdown > order any more. > > Also it causes the devices_kset list to be constantly reordered > until all drivers have been probed which is totally pointless > overhead in the majority of cases and it only covered an issue > with system shutdown, while system-wide suspend/resume potentially > had the same issue on the affected platforms (which was not covered). > > Moreover, the shutdown issue originally addressed by the change in > really_probe() made by commit 52cdbdd49853 is not present in 4.18-rc > any more, since dra7 started to use the sdhci-omap driver which > doesn't disable any regulators during shutdown, so the really_probe() > part of commit 52cdbdd49853 can be safely reverted. [The original > issue was related to the omap_hsmmc driver used by dra7 previously.] > > For the above reasons, revert the really_probe() modifications made > by commit 52cdbdd49853. > > The other code changes made by commit 52cdbdd49853 are useful and > they need not be reverted. > > Fixes: 52cdbdd49853 (driver core: correct device's shutdown order) > Link: https://lore.kernel.org/lkml/CAFgQCTt7VfqM=UyCnvNFxrSw8Z6cUtAi3HUwR4_xPAc03SgHjQ@xxxxxxxxxxxxxx/ > Reported-by: Pingfan Liu <kernelfans@xxxxxxxxx> > Tested-by: Pingfan Liu <kernelfans@xxxxxxxxx> > Reviewed-by: Kishon Vijay Abraham I <kishon@xxxxxx> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > --- > > -> v2: Added information from Kishon on the fact that it should be safe > to revert the really_probe() modifications added by the > problematic commit. Also added the Reviewed-by tag from Kishon. Looks good to me, want me to queue it up in my tree, or are you going to send it on to Linus? And shouldn't this have a stable tag as well? thanks, greg k-h
