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Subject: Re: [PATCH v2] PM / devfreq: rk3399_dmc: Fix kernel oops when
 rockchip,pmu is absent
To:     Marc Zyngier <maz@kernel.org>
Cc:     Enric Balletbo i Serra <enric.balletbo@collabora.com>,
        =?UTF-8?Q?Heiko_St=c3=bcbner?= <heiko@sntech.de>,
        MyungJoo Ham <myungjoo.ham@samsung.com>,
        Kyungmin Park <kyungmin.park@samsung.com>,
        linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
        kernel-team@android.com, stable@vger.kernel.org
From:   Chanwoo Choi <cw00.choi@samsung.com>
Organization: Samsung Electronics
Message-ID: <20fe48e9-62bc-69e4-6cea-2499f6fd2b60@samsung.com>
Date:   Tue, 30 Jun 2020 09:49:32 +0900
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Hi Marc,
Hi Marc,

On 6/29/20 10:22 PM, Marc Zyngier wrote:
> On 2020-06-29 12:29, Chanwoo Choi wrote:
>> Hi Enric and Mark,
>>
>> On 6/29/20 8:05 PM, Enric Balletbo i Serra wrote:
>>> Hi Chanwoo and Marc,
>>>
>>> On 29/6/20 13:09, Chanwoo Choi wrote:
>>>> Hi Enric,
>>>>
>>>> Could you check this issue? Your patch[1] causes this issue.
>>>> As Marc mentioned, although rk3399-dmc.c handled 'rockchip,pmu'
>>>> as the mandatory property, your patch[1] didn't add the 'rockchip,pmu'
>>>> property to the documentation.
>>>>
>>>
>>> I think the problem is that the DT binding patch, for some reason, was missed
>>> and didn't land. The patch seems to have all the required reviews and acks.
>>>
>>>   https://patchwork.kernel.org/patch/10901593/
>>>
>>> Sorry because I didn't notice this issue when 9173c5ceb035 landed. And thanks
>>> for fixing the issue.
>>
>> If the 'rockchip,pmu' propery is mandatory, instead of Mark's patch,
>> we better to require the merge of patch[1] to DT maintainer.
> 
> It is way too late. Firmware exists (mainline u-boot, for one) that
> do not expose the new property, and you can't demand that people
> upgrade. This is an ABI bug, and we now have to live with it.

As you commented, it is proper that rk3399-dmc.c treats 'rockchip,pmu'
property as optional. Could you send v3 with edited patch descritpion
and adding stable mailing list to Cc?

> 
> So, yes to fixing the DT, and no to *only* fixing the DT.

-- 
Best Regards,
Chanwoo Choi
Samsung Electronics