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Message-ID: <f1c3557a-a24b-9764-ff3f-9df352e37188@redhat.com>
Date:   Tue, 1 Feb 2022 14:55:48 +0100
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Subject: Re: [PATCH 1/4] drm: Add I2C connector type
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To:     =?UTF-8?Q?Noralf_Tr=c3=b8nnes?= <noralf@tronnes.org>,
        Sam Ravnborg <sam@ravnborg.org>
Cc:     linux-fbdev@vger.kernel.org, David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        Emil Velikov <emil.l.velikov@gmail.com>,
        linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Maxime Ripard <maxime@cerno.tech>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>
References: <20220131201225.2324984-1-javierm@redhat.com>
 <20220131201225.2324984-2-javierm@redhat.com> <YfhMESTylI1NTKDg@ravnborg.org>
 <4d9a56a7-da25-b411-61cc-372c6fa9011d@tronnes.org>
 <4322f58b-dbeb-b90f-2770-d6881f8005b4@redhat.com>
 <a6f267ea-7617-7d0e-06cd-7ec9c88576c3@tronnes.org>
From:   Javier Martinez Canillas <javierm@redhat.com>
In-Reply-To: <a6f267ea-7617-7d0e-06cd-7ec9c88576c3@tronnes.org>
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On 2/1/22 14:20, Noralf Trønnes wrote:
> 
> 
> Den 01.02.2022 14.06, skrev Javier Martinez Canillas:
>> Hello Noralf,
>>
>> On 2/1/22 13:58, Noralf Trønnes wrote:
>>>
>>>
>>> Den 31.01.2022 21.52, skrev Sam Ravnborg:
>>>> On Mon, Jan 31, 2022 at 09:12:21PM +0100, Javier Martinez Canillas wrote:
>>>>> There isn't a connector type for display controllers accesed through I2C,
>>>>> most drivers use DRM_MODE_CONNECTOR_Unknown or DRM_MODE_CONNECTOR_VIRTUAL.
>>>>>
>>>>> Add an I2C connector type to match the actual connector.
>>>>>
>>>>> As Noralf Trønnes mentions in commit fc06bf1d76d6 ("drm: Add SPI connector
>>>>> type"), user-space should be able to cope with a connector type that does
>>>>> not yet understand.
>>>>>
>>>
>>> It turned out that I wasn't entirely correct here, mpv didn't cope with
>>> unknown types. In the PR to add support Emil Velikov wondered if libdrm
>>> should handle these connector names:
>>> https://github.com/mpv-player/mpv/pull/8989#issuecomment-879187711
>>>
>>
>> I see, thanks for the information. What should we do then, just use the type
>> DRM_MODE_CONNECTOR_Unknown then ?
>>
> 
> Not really, I just wanted to point out that it could be that not all
> userspace will handle an unknown connector type (I just checked the DE's
> at the time). I haven't seen any issues after adding the SPI type so it
> can't be that many apps that has problems. Adding to that a tiny
> monochrome display is limited in which applications it will encounter I
> guess :) It was after adding the USB type that I discovered that mpv
> didn't work.
> 

Anything we do for this rather obscure hardware certainly won't be an
issue for most applications :)

But I wasn't sure if your previous comment meant that you were nacking
$subject. Glad that we can go ahead and describe the correct type then.

Best regards,
-- 
Javier Martinez Canillas
Linux Engineering
Red Hat