[PATCH v6] drm/dp_mst: Fix W=1 warnings

From: Benjamin Gaignard
Date: Wed Feb 05 2020 - 03:50:35 EST

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Fix the warnings that show up with W=1.
They are all about unused but set variables.
If functions returns are not used anymore make them void.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxx>
Reviewed-by: Lyude Paul <lyude@xxxxxxxxxx>
---
version 6:
- change drm_dp_check_mstb_guid() prototype to be able to return an error
- add check for drm_dp_check_mstb_guid() return value
- check drm_dp_dpcd_read() return value in drm_dp_mst_dump_topology()

version 5:
- fix indentation

version 4:
- do not touch crc4 unused variable in this patch
CC: lyude@xxxxxxxxxx
CC: airlied@xxxxxxxx
CC: jani.nikula@xxxxxxxxxxxxxxx

drivers/gpu/drm/drm_dp_mst_topology.c | 114 +++++++++++++++++++---------------
1 file changed, 65 insertions(+), 49 deletions(-)

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 4104f15f4594..0ced7a204985 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -1034,7 +1034,8 @@ static bool drm_dp_sideband_parse_req(struct drm_dp_sideband_msg_rx *raw,
}
}

-static int build_dpcd_write(struct drm_dp_sideband_msg_tx *msg, u8 port_num, u32 offset, u8 num_bytes, u8 *bytes)
+static void build_dpcd_write(struct drm_dp_sideband_msg_tx *msg,
+ u8 port_num, u32 offset, u8 num_bytes, u8 *bytes)
{
struct drm_dp_sideband_msg_req_body req;

@@ -1044,17 +1045,14 @@ static int build_dpcd_write(struct drm_dp_sideband_msg_tx *msg, u8 port_num, u32
req.u.dpcd_write.num_bytes = num_bytes;
req.u.dpcd_write.bytes = bytes;
drm_dp_encode_sideband_req(&req, msg);
-
- return 0;
}

-static int build_link_address(struct drm_dp_sideband_msg_tx *msg)
+static void build_link_address(struct drm_dp_sideband_msg_tx *msg)
{
struct drm_dp_sideband_msg_req_body req;

req.req_type = DP_LINK_ADDRESS;
drm_dp_encode_sideband_req(&req, msg);
- return 0;
}

static int build_clear_payload_id_table(struct drm_dp_sideband_msg_tx *msg)
@@ -1066,7 +1064,8 @@ static int build_clear_payload_id_table(struct drm_dp_sideband_msg_tx *msg)
return 0;
}

-static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg, int port_num)
+static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg,
+ int port_num)
{
struct drm_dp_sideband_msg_req_body req;

@@ -1077,10 +1076,11 @@ static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg, int por
return 0;
}

-static int build_allocate_payload(struct drm_dp_sideband_msg_tx *msg, int port_num,
- u8 vcpi, uint16_t pbn,
- u8 number_sdp_streams,
- u8 *sdp_stream_sink)
+static void build_allocate_payload(struct drm_dp_sideband_msg_tx *msg,
+ int port_num,
+ u8 vcpi, uint16_t pbn,
+ u8 number_sdp_streams,
+ u8 *sdp_stream_sink)
{
struct drm_dp_sideband_msg_req_body req;
memset(&req, 0, sizeof(req));
@@ -1093,11 +1093,10 @@ static int build_allocate_payload(struct drm_dp_sideband_msg_tx *msg, int port_n
number_sdp_streams);
drm_dp_encode_sideband_req(&req, msg);
msg->path_msg = true;
- return 0;
}

-static int build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg,
- int port_num, bool power_up)
+static void build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg,
+ int port_num, bool power_up)
{
struct drm_dp_sideband_msg_req_body req;

@@ -1109,7 +1108,6 @@ static int build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg,
req.u.port_num.port_number = port_num;
drm_dp_encode_sideband_req(&req, msg);
msg->path_msg = true;
- return 0;
}

static int drm_dp_mst_assign_payload_id(struct drm_dp_mst_topology_mgr *mgr,
@@ -2052,29 +2050,24 @@ ssize_t drm_dp_mst_dpcd_write(struct drm_dp_aux *aux,
offset, size, buffer);
}

-static void drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid)
+static int drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid)
{
- int ret;
+ int ret = 0;

memcpy(mstb->guid, guid, 16);

if (!drm_dp_validate_guid(mstb->mgr, mstb->guid)) {
if (mstb->port_parent) {
- ret = drm_dp_send_dpcd_write(
- mstb->mgr,
- mstb->port_parent,
- DP_GUID,
- 16,
- mstb->guid);
+ ret = drm_dp_send_dpcd_write(mstb->mgr,
+ mstb->port_parent,
+ DP_GUID, 16, mstb->guid);
} else {
-
- ret = drm_dp_dpcd_write(
- mstb->mgr->aux,
- DP_GUID,
- mstb->guid,
- 16);
+ ret = drm_dp_dpcd_write(mstb->mgr->aux,
+ DP_GUID, mstb->guid, 16);
}
}
+
+ return ret;
}

static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,
@@ -2595,7 +2588,8 @@ static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
return false;
}

-static int build_dpcd_read(struct drm_dp_sideband_msg_tx *msg, u8 port_num, u32 offset, u8 num_bytes)
+static void build_dpcd_read(struct drm_dp_sideband_msg_tx *msg,
+ u8 port_num, u32 offset, u8 num_bytes)
{
struct drm_dp_sideband_msg_req_body req;

@@ -2604,8 +2598,6 @@ static int build_dpcd_read(struct drm_dp_sideband_msg_tx *msg, u8 port_num, u32
req.u.dpcd_read.dpcd_address = offset;
req.u.dpcd_read.num_bytes = num_bytes;
drm_dp_encode_sideband_req(&req, msg);
-
- return 0;
}

static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr *mgr,
@@ -2828,7 +2820,7 @@ static int 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;
struct drm_dp_mst_port *port, *tmp;
- int i, len, ret, port_mask = 0;
+ int i, ret, port_mask = 0;
bool changed = false;

txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
@@ -2836,7 +2828,7 @@ static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
return -ENOMEM;

txmsg->dst = mstb;
- len = build_link_address(txmsg);
+ build_link_address(txmsg);

mstb->link_address_sent = true;
drm_dp_queue_down_tx(mgr, txmsg);
@@ -2857,7 +2849,9 @@ static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
DRM_DEBUG_KMS("link address reply: %d\n", reply->nports);
drm_dp_dump_link_address(reply);

- drm_dp_check_mstb_guid(mstb, reply->guid);
+ ret = drm_dp_check_mstb_guid(mstb, reply->guid);
+ if (ret)
+ goto out;

for (i = 0; i < reply->nports; i++) {
port_mask |= BIT(reply->ports[i].port_number);
@@ -2898,14 +2892,14 @@ void drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
struct drm_dp_mst_branch *mstb)
{
struct drm_dp_sideband_msg_tx *txmsg;
- int len, ret;
+ int ret;

txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
if (!txmsg)
return;

txmsg->dst = mstb;
- len = build_clear_payload_id_table(txmsg);
+ build_clear_payload_id_table(txmsg);

drm_dp_queue_down_tx(mgr, txmsg);

@@ -2923,7 +2917,6 @@ drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
{
struct drm_dp_enum_path_resources_ack_reply *path_res;
struct drm_dp_sideband_msg_tx *txmsg;
- int len;
int ret;

txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
@@ -2931,7 +2924,7 @@ drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
return -ENOMEM;

txmsg->dst = mstb;
- len = build_enum_path_resources(txmsg, port->port_num);
+ build_enum_path_resources(txmsg, port->port_num);

drm_dp_queue_down_tx(mgr, txmsg);

@@ -3014,7 +3007,7 @@ static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
{
struct drm_dp_sideband_msg_tx *txmsg;
struct drm_dp_mst_branch *mstb;
- int len, ret, port_num;
+ int ret, port_num;
u8 sinks[DRM_DP_MAX_SDP_STREAMS];
int i;

@@ -3039,9 +3032,9 @@ static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
sinks[i] = i;

txmsg->dst = mstb;
- len = build_allocate_payload(txmsg, port_num,
- id,
- pbn, port->num_sdp_streams, sinks);
+ build_allocate_payload(txmsg, port_num,
+ id,
+ pbn, port->num_sdp_streams, sinks);

drm_dp_queue_down_tx(mgr, txmsg);

@@ -3070,7 +3063,7 @@ int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
struct drm_dp_mst_port *port, bool power_up)
{
struct drm_dp_sideband_msg_tx *txmsg;
- int len, ret;
+ int ret;

port = drm_dp_mst_topology_get_port_validated(mgr, port);
if (!port)
@@ -3083,7 +3076,7 @@ int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
}

txmsg->dst = port->parent;
- len = build_power_updown_phy(txmsg, port->port_num, power_up);
+ build_power_updown_phy(txmsg, port->port_num, power_up);
drm_dp_queue_down_tx(mgr, txmsg);

ret = drm_dp_mst_wait_tx_reply(port->parent, txmsg);
@@ -3305,7 +3298,6 @@ static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
struct drm_dp_mst_port *port,
int offset, int size, u8 *bytes)
{
- int len;
int ret = 0;
struct drm_dp_sideband_msg_tx *txmsg;
struct drm_dp_mst_branch *mstb;
@@ -3320,7 +3312,7 @@ static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
goto fail_put;
}

- len = build_dpcd_read(txmsg, port->port_num, offset, size);
+ build_dpcd_read(txmsg, port->port_num, offset, size);
txmsg->dst = port->parent;

drm_dp_queue_down_tx(mgr, txmsg);
@@ -3358,7 +3350,6 @@ static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
struct drm_dp_mst_port *port,
int offset, int size, u8 *bytes)
{
- int len;
int ret;
struct drm_dp_sideband_msg_tx *txmsg;
struct drm_dp_mst_branch *mstb;
@@ -3373,7 +3364,7 @@ static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
goto fail_put;
}

- len = build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
+ build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
txmsg->dst = mstb;

drm_dp_queue_down_tx(mgr, txmsg);
@@ -3619,7 +3610,12 @@ int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr,
DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n");
goto out_fail;
}
- drm_dp_check_mstb_guid(mgr->mst_primary, guid);
+
+ ret = drm_dp_check_mstb_guid(mgr->mst_primary, guid);
+ if (ret) {
+ DRM_DEBUG_KMS("check mstb failed - undocked during suspend?\n");
+ goto out_fail;
+ }

/*
* For the final step of resuming the topology, we need to bring the
@@ -4532,15 +4528,34 @@ void drm_dp_mst_dump_topology(struct seq_file *m,
int ret;

ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, buf, DP_RECEIVER_CAP_SIZE);
+ if (ret) {
+ seq_printf(m, "dpcd read failed\n");
+ goto out;
+ }
seq_printf(m, "dpcd: %*ph\n", DP_RECEIVER_CAP_SIZE, buf);
+
ret = drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf, 2);
+ if (ret) {
+ seq_printf(m, "faux/mst read failed\n");
+ goto out;
+ }
seq_printf(m, "faux/mst: %*ph\n", 2, buf);
+
ret = drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL, buf, 1);
+ if (ret) {
+ seq_printf(m, "mst ctrl read failed\n");
+ goto out;
+ }
seq_printf(m, "mst ctrl: %*ph\n", 1, buf);

/* dump the standard OUI branch header */
ret = drm_dp_dpcd_read(mgr->aux, DP_BRANCH_OUI, buf, DP_BRANCH_OUI_HEADER_SIZE);
+ if (ret) {
+ seq_printf(m, "branch oui read failed\n");
+ goto out;
+ }
seq_printf(m, "branch oui: %*phN devid: ", 3, buf);
+
for (i = 0x3; i < 0x8 && buf[i]; i++)
seq_printf(m, "%c", buf[i]);
seq_printf(m, " revision: hw: %x.%x sw: %x.%x\n",
@@ -4549,6 +4564,7 @@ void drm_dp_mst_dump_topology(struct seq_file *m,
seq_printf(m, "payload table: %*ph\n", DP_PAYLOAD_TABLE_SIZE, buf);
}

+out:
mutex_unlock(&mgr->lock);

}
--
2.15.0

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