linux-kernel - Re: [RFC][PATCH] drm: kirin: Fix dsi probe/attach logic

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Message-ID: <16c9066b-091f-6d0e-23f1-2c1f83a7da1b@samsung.com>
Date:   Thu, 12 Sep 2019 15:21:24 +0200
From:   Andrzej Hajda <a.hajda@...sung.com>
To:     John Stultz <john.stultz@...aro.org>
Cc:     Rob Clark <robdclark@...il.com>,
        Jernej Skrabec <jernej.skrabec@...l.net>,
        Jonas Karlman <jonas@...boo.se>,
        David Airlie <airlied@...ux.ie>,
        Neil Armstrong <narmstrong@...libre.com>,
        lkml <linux-kernel@...r.kernel.org>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        Xinliang Liu <z.liuxinliang@...ilicon.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Sean Paul <seanpaul@...omium.org>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Rongrong Zou <zourongrong@...il.com>,
        Sam Ravnborg <sam@...nborg.org>,
        Matt Redfearn <matt.redfearn@...nci.com>,
        Amit Pundir <amit.pundir@...aro.org>
Subject: Re: [RFC][PATCH] drm: kirin: Fix dsi probe/attach logic

On 12.09.2019 04:38, John Stultz wrote:
> On Wed, Sep 4, 2019 at 3:26 AM Andrzej Hajda <a.hajda@...sung.com> wrote:
>> On 03.09.2019 18:18, John Stultz wrote:
>>> On Mon, Sep 2, 2019 at 6:22 AM Andrzej Hajda <a.hajda@...sung.com> wrote:
>>>> On 30.08.2019 19:00, Rob Clark wrote:
>>>>> On Thu, Aug 29, 2019 at 11:52 PM Andrzej Hajda <a.hajda@...sung.com> wrote:
>>>>>> Of course it seems you have different opinion what is the right thing in
>>>>>> this case, so if you convince us that your approach is better one can
>>>>>> revert the patch.
>>>>> I guess my strongest / most immediate opinion is to not break other
>>>>> existing adv75xx bridge users.
>>>> It is pity that breakage happened, and next time we should be more
>>>> strict about testing other platforms, before patch acceptance.
>>>>
>>>> But reverting it now will break also platform which depend on it.
>>> I'm really of no opinion of which approach is better here, but I will
>>> say that when a patch breaks previously working boards, that's a
>>> regression and justifying that some other board is now enabled that
>>> would be broken by the revert (of a patch that is not yet upstream)
>>> isn't really a strong argument.
>>>
>>> I'm happy to work with folks to try to fixup the kirin driver if this
>>> patch really is the right approach, but we need someone to do the same
>>> for the db410c, and I don't think its fair to just dump that work onto
>>> folks under the threat of the board breaking.
>>
>> These drivers should be fixed anyway - assumption that
>> drm_bridge/drm_panel will be registered before the bus it is attached to
>> is just incorrect.
>>
>> So instead of reverting, fixing and then re-applying the patch I have
>> gently proposed shorter path. If you prefer long path we can try to go
>> this way.
>>
>> Matt, is the pure revert OK for you or is it possible to prepare some
>> workaround allowing cooperation with both approaches?
> Rob/Andrzej: What's the call here?
>
> Should I resubmit the kirin fix for the adv7511 regression here?
> Or do we revert the adv7511 patch? I believe db410c still needs a fix.
>
> I'd just like to keep the HiKey board from breaking, so let me know so
> I can get the fix submitted if needed.


Since there is no response from Matt, we can perform revert, since there
are no other ideas. I will apply it tomorrow, if there are no objections.

And for the future: I guess it is not possible to make adv work with old
and new approach, but simple workaround for adv could be added later:

if (source is msm or kirin)

    do_the_old_way

else

    do_correctly.


And remove it after fixing both dsi masters.


Regards

Andrzej


>
> thanks
> -john
>
>