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

On 2/1/22 14:20, Noralf Trønnes wrote:

Den 01.02.2022 14.06, skrev Javier Martinez Canillas:

quoted

Hello Noralf,

On 2/1/22 13:58, Noralf Trønnes wrote:

quoted

Den 31.01.2022 21.52, skrev Sam Ravnborg:

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On Mon, Jan 31, 2022 at 09:12:21PM +0100, Javier Martinez Canillas wrote:

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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