From: Kishon Vijay Abraham I <kishon@ti.com>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Pingfan Liu <kernelfans@gmail.com>,
<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@vger.kernel.org>,
Lukas Wunner <lukas@wunner.de>,
Linux PM <linux-pm@vger.kernel.org>
Subject: Re: [PATCH] driver core: Partially revert "driver core: correct device's shutdown order"
Date: Tue, 10 Jul 2018 17:52:28 +0530 [thread overview]
Message-ID: <aa41cfa9-dedb-5f19-0d85-0d4c19d26ea8@ti.com> (raw)
In-Reply-To: <2927655.Y1qg3UnIrE@aspire.rjw.lan>
Hi,
On Tuesday 10 July 2018 05:05 PM, 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 covers an issue
> with system shutdown, while system-wide suspend/resume potentially
> has the same issue on the affected platforms (which is not covered).
>
> For that reason, revert the really_probe() modifications made by
> commit 52cdbdd49853 which unfortunately will expose the shutdown
> issue the problematic commit attempted to fix (and which will have
> to be addressed differently and correctly in the future).
>
> 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>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
This issue because of which 52cdbdd49853 (driver core: correct device's
shutdown order) was added is not present from 4.18, since dra7 started using
sdhci-omap.c driver which doesn't disable regulator during shutdown. (The
original issue was present in omap_hsmmc driver).
When sdhci-omap driver is modified to disable regulator during shutdown,
something like device_link_add() can be added in _regulator_get().
Since this doesn't reintroduce the problem that was solved by 52cdbdd49853,
this can be safely merged.
Reviewed-by: Kishon Vijay Abraham I <kishon@ti.com>
Thanks
Kishon
next prev parent reply other threads:[~2018-07-10 12:23 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 [this message]
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
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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