Re: [PATCH 1/2] Revert "drm: hide unregistered connectors from GETCONNECTOR IOCTL"

["Jonas Ådahl" <jadahl@gmail.com>]

Can you update the commit message so at least the first patch can land
for 6.1 so we can avoid regressions? E.g. something like

````
It caused logically active but disconnected MST display port connectors to
disappear from the drmModeGetResources() list, meaning userspace is made to
believe the connector is already disabled. This conflicts with the intended
behavior of userspace, which is to detect the connector got disconnected
and then disabling it.

When userspace later attempts post a new mode set commit, if that commit
uses the same CRTC used to previously drive the disconnected connector,
it will fail as that CRTC is logically still tied to the disconnected
connector.

This was discovered by a bisecting docking station hot plugging
regression using mutter.
```

(feel free to edit in any way you want).


Jonas

On Mon, Oct 17, 2022 at 03:31:57PM +0000, Simon Ser wrote:
> This reverts commit 981f09295687f856d5345e19c7084aca481c1395.
> 
> It turns out this breaks Mutter.
> 
> Signed-off-by: Simon Ser <contact@emersion.fr>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: Lyude Paul <lyude@redhat.com>
> Cc: Jonas Ådahl <jadahl@redhat.com>
> ---
>  drivers/gpu/drm/drm_mode_config.c | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
> index 939d621c9ad4..688c8afe0bf1 100644
> --- a/drivers/gpu/drm/drm_mode_config.c
> +++ b/drivers/gpu/drm/drm_mode_config.c
> @@ -151,9 +151,6 @@ int drm_mode_getresources(struct drm_device *dev, void *data,
>  	count = 0;
>  	connector_id = u64_to_user_ptr(card_res->connector_id_ptr);
>  	drm_for_each_connector_iter(connector, &conn_iter) {
> -		if (connector->registration_state != DRM_CONNECTOR_REGISTERED)
> -			continue;
> -
>  		/* only expose writeback connectors if userspace understands them */
>  		if (!file_priv->writeback_connectors &&
>  		    (connector->connector_type == DRM_MODE_CONNECTOR_WRITEBACK))
> -- 
> 2.38.0
> 
>