Re: [PATCH] drm/dp_mst: Fix W=1 warnings

From: Jani Nikula <jani.nikula@linux.intel.com>
To: Benjamin Gaignard <benjamin.gaignard@st.com>,
	maarten.lankhorst@linux.intel.com, mripard@kernel.org,
	sean@poorly.run, airlied@linux.ie, daniel@ffwll.ch
Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	Benjamin Gaignard <benjamin.gaignard@st.com>
Subject: Re: [PATCH] drm/dp_mst: Fix W=1 warnings
Date: Thu, 28 Nov 2019 12:03:32 +0200	[thread overview]
Message-ID: <877e3knwqz.fsf@intel.com> (raw)
In-Reply-To: <20191112123938.2346-1-benjamin.gaignard@st.com>

On Tue, 12 Nov 2019, Benjamin Gaignard <benjamin.gaignard@st.com> wrote:
> Fix the warnings that show up with W=1.
> They are all about unused but set variables.
>
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
> ---
>  drivers/gpu/drm/drm_dp_mst_topology.c | 50 +++++++++++++----------------------
>  1 file changed, 19 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
> index b854a422a523..6ff554be8000 100644
> --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> @@ -672,7 +672,6 @@ static bool drm_dp_sideband_msg_build(struct drm_dp_sideband_msg_rx *msg,
>  				      u8 *replybuf, u8 replybuflen, bool hdr)
>  {
>  	int ret;
> -	u8 crc4;
>  
>  	if (hdr) {
>  		u8 hdrlen;
> @@ -714,8 +713,6 @@ static bool drm_dp_sideband_msg_build(struct drm_dp_sideband_msg_rx *msg,
>  	}
>  
>  	if (msg->curchunk_idx >= msg->curchunk_len) {
> -		/* do CRC */
> -		crc4 = drm_dp_msg_data_crc4(msg->chunk, msg->curchunk_len - 1);

Someone who knows this code really needs to check if we should be using
crc4 instead of just throwing this away as unused.

>  		/* copy chunk into bigger msg */
>  		memcpy(&msg->msg[msg->curlen], msg->chunk, msg->curchunk_len - 1);
>  		msg->curlen += msg->curchunk_len - 1;
> @@ -1744,14 +1741,13 @@ static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port,
>   */
>  static bool drm_dp_port_setup_pdt(struct drm_dp_mst_port *port)

The function changed in c485e2c97dae ("drm/dp_mst: Refactor pdt
setup/teardown, add more locking").

>  {
> -	int ret;
>  	u8 rad[6], lct;
>  	bool send_link = false;
>  	switch (port->pdt) {
>  	case DP_PEER_DEVICE_DP_LEGACY_CONV:
>  	case DP_PEER_DEVICE_SST_SINK:
>  		/* add i2c over sideband */
> -		ret = drm_dp_mst_register_i2c_bus(&port->aux);
> +		drm_dp_mst_register_i2c_bus(&port->aux);
>  		break;
>  	case DP_PEER_DEVICE_MST_BRANCHING:
>  		lct = drm_dp_calculate_rad(port, rad);
> @@ -1821,21 +1817,18 @@ ssize_t drm_dp_mst_dpcd_write(struct drm_dp_aux *aux,
>  
>  static void drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid)
>  {
> -	int ret;
> -
>  	memcpy(mstb->guid, guid, 16);
>  
>  	if (!drm_dp_validate_guid(mstb->mgr, mstb->guid)) {
>  		if (mstb->port_parent) {
> -			ret = drm_dp_send_dpcd_write(
> +			drm_dp_send_dpcd_write(
>  					mstb->mgr,
>  					mstb->port_parent,
>  					DP_GUID,
>  					16,
>  					mstb->guid);

Indentation could be fixed while at it.

>  		} else {
> -
> -			ret = drm_dp_dpcd_write(
> +			drm_dp_dpcd_write(
>  					mstb->mgr->aux,
>  					DP_GUID,
>  					mstb->guid,
> @@ -2427,14 +2420,14 @@ static void drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
>  {
>  	struct drm_dp_sideband_msg_tx *txmsg;
>  	struct drm_dp_link_address_ack_reply *reply;
> -	int i, len, ret;
> +	int i, ret;
>  
>  	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
>  	if (!txmsg)
>  		return;
>  
>  	txmsg->dst = mstb;
> -	len = build_link_address(txmsg);
> +	build_link_address(txmsg);