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From: Sasha Levin <Alexander.Levin@microsoft.com>
To: Marc Zyngier <marc.zyngier@arm.com>
CC: "stable@vger.kernel.org" <stable@vger.kernel.org>,
        Olof Johansson <olof@lixom.net>
Subject: Re: [PATCH AUTOSEL 4.18 008/113] iommu/rockchip: Handle errors
 returned from PM framework
Date: Sun, 2 Sep 2018 12:56:21 +0000
Message-ID: <20180902063932.GG35539@sasha-vm>
References: <20180830180050.35735-1-alexander.levin@microsoft.com>
 <20180830180050.35735-8-alexander.levin@microsoft.com>
 <86y3ckwdbi.wl-marc.zyngier@arm.com>
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On Sun, Sep 02, 2018 at 08:47:29AM +0100, Marc Zyngier wrote:
>On Thu, 30 Aug 2018 19:01:16 +0100,
>Sasha Levin <Alexander.Levin@microsoft.com> wrote:
>>
>> From: Marc Zyngier <marc.zyngier@arm.com>
>>
>> [ Upstream commit 3fc7c5c0cff3150e471f5fd12f59971c6d2c6513 ]
>>
>> pm_runtime_get_if_in_use can fail: either PM has been disabled
>> altogether (-EINVAL), or the device hasn't been enabled yet (0).
>> Sadly, the Rockchip IOMMU driver tends to conflate the two things
>> by considering a non-zero return value as successful.
>>
>> This has the consequence of hiding other bugs, so let's handle this
>> case throughout the driver, with a WARN_ON_ONCE so that we can try
>> and work out what happened.
>>
>> Fixes: 0f181d3cf7d98 ("iommu/rockchip: Add runtime PM support")
>> Reviewed-by: Heiko Stuebner <heiko@sntech.de>
>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
>> Signed-off-by: Olof Johansson <olof@lixom.net>
>> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
>
>Picking this patch on its own feels like a bad idea if CONFIG_PM is
>not selected. Consider picking up 7db7a8f5638a and d1558dfd9f22 which
>guarantee that things won't break.

Grabbed those 2 as well, thanks!=