Re: [PATCH 1/4] drm: Add I2C connector type

From: Javier Martinez Canillas
Date: Tue Feb 01 2022 - 08:55:55 EST


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