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From: Sasha Levin <sashal@kernel.org>
To: Chunyan Zhang <zhang.chunyan@linaro.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, linux-kernel@vger.kernel.org,
	Grygorii Strashko <grygorii.Strashko@ti.com>,
	"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
	Chunyan Zhang <zhang.lyra@gmail.com>
Subject: Re: [BACKPORT 4.4.y] PM / sleep: prohibit devices probing during suspend/hibernation
Date: Wed, 5 Jun 2019 21:08:57 -0400	[thread overview]
Message-ID: <20190606010857.GF29739@sasha-vm> (raw)
In-Reply-To: <20190605111412.3461-1-zhang.chunyan@linaro.org>

On Wed, Jun 05, 2019 at 07:14:12PM +0800, Chunyan Zhang wrote:
>From: "Strashko, Grygorii" <grygorii.strashko@ti.com>
>
>[ Upstream commit 013c074f8642d8e815ad670601f8e27155a74b57 ]
>
>It is unsafe [1] if probing of devices will happen during suspend or
>hibernation and system behavior will be unpredictable in this case.
>So, let's prohibit device's probing in dpm_prepare() and defer their
>probing instead. The normal behavior will be restored in
>dpm_complete().
>
>This patch introduces new DD core APIs:
> device_block_probing()
>   It will disable probing of devices and defer their probes instead.
> device_unblock_probing()
>   It will restore normal behavior and trigger re-probing of deferred
>   devices.
>
>[1] https://lkml.org/lkml/2015/9/11/554
>
>Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
>Acked-by: Pavel Machek <pavel@ucw.cz>
>Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>

This patch had to be fixed a few times (see 015bb5e134 and 9a2a5a638f8),
we can't just take it as is.

It might be just simpler to move to a newer kernel at this point.

--
Thanks,
Sasha

  reply	other threads:[~2019-06-06  1:09 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-05 11:14 [BACKPORT 4.4.y] PM / sleep: prohibit devices probing during suspend/hibernation Chunyan Zhang
2019-06-06  1:08 ` Sasha Levin [this message]
2019-06-10  2:33   ` Chunyan Zhang

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