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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2018-07-10 14:51:33 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-07-28 07:49:13 +0200
commitbf0070e2f56eb3da708978da5dab5d36bbed1bf6 (patch)
treeb7bf897abd17d2cc0de7713b4a58172c6056c484
parent9e10043b6bdcc1a991a029de8a0bc745950345c6 (diff)
driver core: Partially revert "driver core: correct device's shutdown order"
commit 722e5f2b1eec7de61117b7c0a7914761e3da2eda upstream. 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@mail.gmail.com/ Reported-by: Pingfan Liu <kernelfans@gmail.com> Tested-by: Pingfan Liu <kernelfans@gmail.com> Reviewed-by: Kishon Vijay Abraham I <kishon@ti.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/base/dd.c8
1 files changed, 0 insertions, 8 deletions
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index d76cd97a98b6..ee25a69630c3 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -363,14 +363,6 @@ re_probe:
goto probe_failed;
}
- /*
- * Ensure devices are listed in devices_kset in correct order
- * It's important to move Dev to the end of devices_kset before
- * calling .probe, because it could be recursive and parent Dev
- * should always go first
- */
- devices_kset_move_last(dev);
-
if (dev->bus->probe) {
ret = dev->bus->probe(dev);
if (ret)