[PATCH] drm/dp_mst: Zero assigned PBN when releasing VCPI slots

[Lyude Paul]

Reviewed-by: Lyude Paul <lyude at redhat.com>

In the future btw, you should use the DRM maintainer tools to add a Fixed-by
tag, since this:

Fixes: cd82d82cbc04 ("drm/dp_mst: Add branch bandwidth validation to MST
atomic check")

Also so it gets cc'd to stable, I'll fixup the patch and push it. Thanks!

On Tue, 2020-04-07 at 12:07 -0400, mikita.lipski at amd.com wrote:
> From: Mikita Lipski <mikita.lipski at amd.com>
> 
> Zero Port's PBN together with VCPI slots when releasing
> allocated VCPI slots. That way when disabling the connector
> it will not cause issues in drm_dp_mst_atomic_check verifying
> branch bw limit.
> 
> Signed-off-by: Mikita Lipski <mikita.lipski at amd.com>
> ---
>  drivers/gpu/drm/drm_dp_mst_topology.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c
> b/drivers/gpu/drm/drm_dp_mst_topology.c
> index 38bf111e5f9b..ed109dd15df6 100644
> --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> @@ -4276,6 +4276,7 @@ int drm_dp_atomic_release_vcpi_slots(struct
> drm_atomic_state *state,
>  	if (pos->vcpi) {
>  		drm_dp_mst_put_port_malloc(port);
>  		pos->vcpi = 0;
> +		pos->pbn = 0;
>  	}
>  
>  	return 0;
-- 
Cheers,
	Lyude Paul (she/her)
	Associate Software Engineer at Red Hat