From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
Pingfan Liu <kernelfans@gmail.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Grygorii Strashko <grygorii.strashko@ti.com>,
Christoph Hellwig <hch@infradead.org>,
Bjorn Helgaas <helgaas@kernel.org>,
Dave Young <dyoung@redhat.com>,
Linux PCI <linux-pci@vger.kernel.org>,
Lukas Wunner <lukas@wunner.de>,
Linux PM <linux-pm@vger.kernel.org>,
Kishon Vijay Abraham I <kishon@ti.com>
Subject: Re: [PATCH v2] driver core: Partially revert "driver core: correct device's shutdown order"
Date: Tue, 10 Jul 2018 17:47:15 +0200 [thread overview]
Message-ID: <20180710154715.GA20793@kroah.com> (raw)
In-Reply-To: <CAJZ5v0iV0ZaCbhoVOrGx08f6Y7Ei2q+qazxEMQRYD4LAq9LUbA@mail.gmail.com>
On Tue, Jul 10, 2018 at 05:40:21PM +0200, Rafael J. Wysocki wrote:
> On Tue, Jul 10, 2018 at 2:59 PM, Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> > On Tue, Jul 10, 2018 at 02:51:33PM +0200, Rafael J. Wysocki wrote:
> >> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> >>
> >> 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>
> >> ---
> >>
> >> -> 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?
>
> Please queue it up.
>
> > And shouldn't this have a stable tag as well?
>
> That is sort of a gray area, because I think it may expose the
> shutdown issue on dra7 in -stable, but technically it still fixes a
> regression in the driver core. So your call I suppose. :-)
Being bug compatible is key :)
I'll add a stable tag.
thanks,
greg k-h
next prev parent reply other threads:[~2018-07-10 15:47 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-03 6:50 [PATCHv3 0/4] drivers/base: bugfix for supplier<-consumer ordering in device_kset Pingfan Liu
2018-07-03 6:50 ` [PATCHv3 1/4] drivers/base: fold the routine of device's shutdown into a func Pingfan Liu
2018-07-03 6:50 ` [PATCHv3 2/4] drivers/base: utilize device tree info to shutdown devices Pingfan Liu
2018-07-03 7:51 ` Lukas Wunner
2018-07-03 9:26 ` Pingfan Liu
2018-07-04 3:10 ` Pingfan Liu
2018-07-03 10:58 ` Andy Shevchenko
2018-07-03 17:03 ` Pavel Tatashin
2018-07-04 17:04 ` kbuild test robot
2018-07-05 10:11 ` Rafael J. Wysocki
2018-07-06 3:02 ` Pingfan Liu
2018-07-06 9:53 ` Rafael J. Wysocki
2018-07-07 4:02 ` Pingfan Liu
2018-07-06 10:00 ` [PATCH] driver core: Drop devices_kset_move_last() call from really_probe() Rafael J. Wysocki
2018-07-09 13:57 ` Bjorn Helgaas
2018-07-09 21:35 ` Rafael J. Wysocki
2018-07-09 22:06 ` Bjorn Helgaas
2018-07-10 6:19 ` Kishon Vijay Abraham I
2018-07-10 10:32 ` Rafael J. Wysocki
2018-07-10 10:29 ` Rafael J. Wysocki
2018-07-10 6:33 ` Pingfan Liu
2018-07-10 11:35 ` [PATCH] driver core: Partially revert "driver core: correct device's shutdown order" Rafael J. Wysocki
2018-07-10 12:22 ` Kishon Vijay Abraham I
2018-07-10 12:38 ` Rafael J. Wysocki
2018-07-10 12:51 ` [PATCH v2] " Rafael J. Wysocki
2018-07-10 12:59 ` Greg Kroah-Hartman
2018-07-10 15:40 ` Rafael J. Wysocki
2018-07-10 15:47 ` Greg Kroah-Hartman [this message]
2018-07-10 19:13 ` Kishon Vijay Abraham I
2018-07-03 6:50 ` [PATCHv3 3/4] drivers/base: clean up the usage of devices_kset_move_last() Pingfan Liu
2018-07-03 14:26 ` Rafael J. Wysocki
2018-07-04 4:40 ` Pingfan Liu
2018-07-04 10:17 ` Rafael J. Wysocki
2018-07-05 2:32 ` Pingfan Liu
2018-07-03 6:50 ` [PATCHv3 4/4] Revert "driver core: correct device's shutdown order" Pingfan Liu
2018-07-03 14:35 ` [PATCHv3 0/4] drivers/base: bugfix for supplier<-consumer ordering in device_kset Rafael J. Wysocki
2018-07-04 2:47 ` Pingfan Liu
2018-07-04 10:21 ` Rafael J. Wysocki
2018-07-05 2:44 ` Pingfan Liu
2018-07-05 9:18 ` Rafael J. Wysocki
2018-07-06 8:36 ` Lukas Wunner
2018-07-06 8:47 ` Rafael J. Wysocki
2018-07-06 13:55 ` Pingfan Liu
2018-07-07 4:24 ` Pingfan Liu
2018-07-08 8:25 ` Rafael J. Wysocki
2018-07-09 6:48 ` Pingfan Liu
2018-07-09 7:48 ` Rafael J. Wysocki
2018-07-09 8:40 ` Pingfan Liu
2018-07-09 8:58 ` Rafael J. Wysocki
2018-07-06 10:02 ` Kishon Vijay Abraham I
2018-07-06 13:52 ` Pingfan Liu
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