[Nouveau] [PATCH] Accept 3d controllers and not only VGA controllers.

[Tobias Klausmann]

On 11/10/17 7:49 PM, Josef Larsson wrote:
> Accept 3d controllers and not only VGA controllers. According to Ilia
> Mirkin,
> the VGA controller check should be removed. This makes it possible
> to use external connectors on a docking station (40A5) for a Thinkpad P51.
> (See Bug 101778).
>
> lspci example:
>
> 01:00.0 3D controller: NVIDIA Corporation GM107GLM [Quadro M1200 Mobile]
> (rev a2)
>
> Also include safe-guards to avoid NULL dereferencing of fbcon, which is
> how this bug was found.
> ---
>   drivers/gpu/drm/nouveau/nouveau_fbcon.c |  3 +--
>   drivers/gpu/drm/nouveau/nv50_display.c  | 13 +++++++++++++
>   2 files changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/nouveau/nouveau_fbcon.c
> b/drivers/gpu/drm/nouveau/nouveau_fbcon.c
> index 2b12d82aac15..6b4d374a9d82 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_fbcon.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_fbcon.c
> @@ -498,8 +498,7 @@ nouveau_fbcon_init(struct drm_device *dev)
>       int preferred_bpp;
>       int ret;
>   
> -    if (!dev->mode_config.num_crtc ||
> -        (dev->pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
> +    if (!dev->mode_config.num_crtc)
>           return 0;
>   
>       fbcon = kzalloc(sizeof(struct nouveau_fbdev), GFP_KERNEL);
> diff --git a/drivers/gpu/drm/nouveau/nv50_display.c
> b/drivers/gpu/drm/nouveau/nv50_display.c
> index fb47d46050ec..061daf036407 100644
> --- a/drivers/gpu/drm/nouveau/nv50_display.c
> +++ b/drivers/gpu/drm/nouveau/nv50_display.c
> @@ -3214,6 +3214,13 @@ nv50_mstm_destroy_connector(struct
> drm_dp_mst_topology_mgr *mgr,
>       struct nouveau_drm *drm = nouveau_drm(connector->dev);
>       struct nv50_mstc *mstc = nv50_mstc(connector);
>   
> +    if (!drm->fbcon)
> +    {
> +        NV_WARN(drm, "drm->fbcon of %s point to NULL. Will not destroy
> connector\n",
> +            connector->name);
> +        return;
> +    }
> +
>       drm_connector_unregister(&mstc->connector);
>   
>       drm_modeset_lock_all(drm->dev);
> @@ -3229,6 +3236,12 @@ nv50_mstm_register_connector(struct drm_connector
> *connector)
>   {
>       struct nouveau_drm *drm = nouveau_drm(connector->dev);
>   
> +    if (!drm->fbcon)
> +    {
> +        NV_WARN(drm, "drm->fbcon of %s point to NULL. Will not register
> connector\n",
> +            connector->name);
> +        return;
> +    }
>       drm_modeset_lock_all(drm->dev);
>       drm_fb_helper_add_one_connector(&drm->fbcon->helper, connector);
>       drm_modeset_unlock_all(drm->dev);
>
>

Hi,

the patch looks OK to me, yet as noted in IRC, i'd like to have this 
patch split into two and have the ->fbcon check as a precondition to the 
3D Controller part. But lets see what the other and more clever people 
think about it! :)

Greetings,

Tobias