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Subject: Re: [PATCH 1/3] drm: mxsfb: Change driver.name to mxsfb-drm
To:     Leonard Crestez <leonard.crestez@nxp.com>,
        "stefan@agner.ch" <stefan@agner.ch>
Cc:     dl-linux-imx <linux-imx@nxp.com>,
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        "linux-fbdev@vger.kernel.org" <linux-fbdev@vger.kernel.org>,
        Fabio Estevam <fabio.estevam@nxp.com>,
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        "marek.vasut@gmail.com" <marek.vasut@gmail.com>
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From:   Marek Vasut <marex@denx.de>
Message-ID: <039b2914-3393-5e81-82a6-7d517c5818a9@denx.de>
Date:   Thu, 12 Jul 2018 15:14:57 +0200
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On 07/12/2018 03:03 PM, Leonard Crestez wrote:
> On Thu, 2018-07-12 at 11:21 +0200, Stefan Agner wrote:
>> On 10.07.2018 11:11, Marek Vasut wrote:
>>> On 07/10/2018 11:06 AM, Stefan Agner wrote:
>>>> This is one of the situation where states quo is kinda the worst
>>>> situation.
>>>>
>>>> Currently imx_v6_v7_defconfig and mxs_defconfig actually still uses
>>>> CONFIG_FB_MXS.
>>>>
>>>> I understand that you'd rather prefer to move forward. I suggest we do
>>>> it in steps.
>>>>
>>>> In 4.19:
>>>>
>>>> - Change DRM driver.name to mxsfb-drm so we avoid conflicts for now
>>>
>>> But this will break mesa if it depends on mxsfb name for ie. etnaviv
>>> binding.
>>
>> Does it? grep -r -e mxsfb in libdrm and mesa master returns nothing.
>>
>> There is also .name in struct drm_driver, which is already set to
>> mxsfb-drm... Is that the one exposed to user space?
> 
> Running etnaviv+x11 with a renamed mxsfb driver works fine on imx6sx-
> sdb.
> 
> Tools like modetest already need -M mxsfb-drm, the drm_driver.name
> seems to be what matters.
> 
>> - Remove CONFIG_FB_MXS from imx_v6_v7_defconfig/mxs_defconfig now, and
>> only enable CONFIG_DRM_MXSFB=y
> 
> If one of the drivers is renamed then they can coexist: since the
> bindings are distinct one driver will return a probe error and the
> other will bind successfully. This can even be adjusted so that it
> doesn't even print ugly scary errors.
> 
> This can last until somebody implements support for old bindings in the
> drm driver and then FB_MXS can just be deleted.

So why don't we just convert the DT bindings on boards supported
upstream and zap the old driver ? What is the problem with that?

Realistically, how many MXS boards in the field use old DT and new kernel ?

-- 
Best regards,
Marek Vasut