linux-kernel - Re: [PATCH 03/42] drm/drm_dp_mst_topology: Remove set but never used variable 'len'

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Date:   Tue, 17 Nov 2020 18:29:25 +0100
From:   Daniel Vetter <daniel@...ll.ch>
To:     Lee Jones <lee.jones@...aro.org>
Cc:     linux-kernel@...r.kernel.org,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH 03/42] drm/drm_dp_mst_topology: Remove set but never used
 variable 'len'

On Mon, Nov 16, 2020 at 05:40:33PM +0000, Lee Jones wrote:
> Fixes the following W=1 kernel build warning(s):
> 
>  drivers/gpu/drm/drm_dp_mst_topology.c: In function ‘drm_dp_send_query_stream_enc_status’:
>  drivers/gpu/drm/drm_dp_mst_topology.c:3263:6: warning: variable ‘len’ set but not used [-Wunused-but-set-variable]
> 
> Cc: Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>
> Cc: Maxime Ripard <mripard@...nel.org>
> Cc: Thomas Zimmermann <tzimmermann@...e.de>
> Cc: David Airlie <airlied@...ux.ie>
> Cc: Daniel Vetter <daniel@...ll.ch>
> Cc: dri-devel@...ts.freedesktop.org
> Signed-off-by: Lee Jones <lee.jones@...aro.org>

Going to apply this, but I noticed that the return value of the
build_query_stream_enc_status() is pointless. Can you pls follow up with
an additional patch to change that to void?

Thanks, Daniel

> ---
>  drivers/gpu/drm/drm_dp_mst_topology.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
> index e875425336406..0401b2f475002 100644
> --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> @@ -3260,7 +3260,7 @@ int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
>  {
>  	struct drm_dp_sideband_msg_tx *txmsg;
>  	u8 nonce[7];
> -	int len, ret;
> +	int ret;
>  
>  	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
>  	if (!txmsg)
> @@ -3281,7 +3281,7 @@ int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
>  	 */
>  	txmsg->dst = mgr->mst_primary;
>  
> -	len = build_query_stream_enc_status(txmsg, port->vcpi.vcpi, nonce);
> +	build_query_stream_enc_status(txmsg, port->vcpi.vcpi, nonce);
>  
>  	drm_dp_queue_down_tx(mgr, txmsg);
>  
> -- 
> 2.25.1
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch