linux-kernel - Re: [Intel-gfx] [PATCH v5 04/10] drm/dp_mst: Remove all evil duplicate state pointers

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Date:   Mon, 2 Apr 2018 23:23:45 +0000
From:   "Pandiyan, Dhinakaran" <dhinakaran.pandiyan@...el.com>
To:     "lyude@...hat.com" <lyude@...hat.com>
CC:     "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "intel-gfx@...ts.freedesktop.org" <intel-gfx@...ts.freedesktop.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "airlied@...ux.ie" <airlied@...ux.ie>
Subject: Re: [Intel-gfx] [PATCH v5 04/10] drm/dp_mst: Remove all evil
 duplicate state pointers

On Mon, 2018-04-02 at 18:47 -0400, Lyude Paul wrote:
> There's no reason to track the atomic state three times. Unfortunately,
> this is currently what we're doing, and even worse is that there is only
> one actually correct state pointer: the one in mst_state->base.state.
> mgr->state never seems to be used, along with the one in
> mst_state->state.
> 

Looks like the redundancy got introduced when struct drm_private_state
was added.

Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@...el.com>

> This confused me for over 4 hours until I realized there was no magic
> behind these pointers. So, let's save everyone else from the trouble.
> 
> Signed-off-by: Lyude Paul <lyude@...hat.com>.
> Cc: Manasi Navare <manasi.d.navare@...el.com>
> Cc: Ville Syrjälä <ville.syrjala@...ux.intel.com>
> Signed-off-by: Lyude Paul <lyude@...hat.com>
> ---
>  include/drm/drm_dp_mst_helper.h | 6 ------
>  1 file changed, 6 deletions(-)
> 
> diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
> index 41a8f08da05d..035963fbcd9d 100644
> --- a/include/drm/drm_dp_mst_helper.h
> +++ b/include/drm/drm_dp_mst_helper.h
> @@ -409,7 +409,6 @@ struct drm_dp_payload {
>  struct drm_dp_mst_topology_state {
>  	struct drm_private_state base;
>  	int avail_slots;
> -	struct drm_atomic_state *state;
>  	struct drm_dp_mst_topology_mgr *mgr;
>  };
>  
> @@ -497,11 +496,6 @@ struct drm_dp_mst_topology_mgr {
>  	 */
>  	int pbn_div;
>  
> -	/**
> -	 * @state: State information for topology manager
> -	 */
> -	struct drm_dp_mst_topology_state *state;
> -
>  	/**
>  	 * @funcs: Atomic helper callbacks
>  	 */