[PATCH v3] drm/dp_mst: Fix W=1 warnings
Lyude Paul
lyude at redhat.com
Thu Jan 30 22:22:13 UTC 2020
On Mon, 2020-01-27 at 14:08 +0100, Benjamin Gaignard wrote:
> Le ven. 24 janv. 2020 à 23:08, Lyude Paul <lyude at redhat.com> a écrit :
> > On Tue, 2020-01-07 at 14:11 +0100, Benjamin Gaignard wrote:
> > > Le ven. 20 déc. 2019 à 15:03, Benjamin Gaignard
> > > <benjamin.gaignard at linaro.org> a écrit :
> > > > Le lun. 16 déc. 2019 à 09:28, Benjamin Gaignard
> > > > <benjamin.gaignard at linaro.org> a écrit :
> > > > > Le mer. 4 déc. 2019 à 17:47, Jani Nikula <
> > > > > jani.nikula at linux.intel.com> a
> > > > > écrit :
> > > > > > On Thu, 28 Nov 2019, Benjamin Gaignard <benjamin.gaignard at st.com>
> > > > > > wrote:
> > > > > > > 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 at st.com>
> > > > > > > ---
> > > > > > > CC: Jani Nikula <jani.nikula at linux.intel.com>
> > > > > > >
> > > > > > > changes in version 3:
> > > > > > > - remove the hunk that may conflict with c485e2c97dae
> > > > > > > ("drm/dp_mst: Refactor pdt setup/teardown, add more locking")
> > > > > > >
> > > > > > > changes in version 2:
> > > > > > > - fix indentations
> > > > > > > - when possible change functions prototype to void
> > > > > > >
> > > > > > > drivers/gpu/drm/drm_dp_mst_topology.c | 83 +++++++++++++------
> > > > > > > ----
> > > > > > > ------------
> > > > > > > 1 file changed, 31 insertions(+), 52 deletions(-)
> > > > > > >
> > > > > > > diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c
> > > > > > > b/drivers/gpu/drm/drm_dp_mst_topology.c
> > > > > > > index 1437bc46368b..d5cb5688b5dd 100644
> > > > > > > --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> > > > > > > +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> > > > > > > @@ -674,7 +674,6 @@ 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;
> > > > > > > @@ -716,8 +715,6 @@ 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);
> > > > > >
> > > > > > Again, someone needs to check if crc4 should be *used* instead of
> > > > > > thrown
> > > > > > away. Blindly throwing stuff out is not the way to go.
> > > > >
> > > > > Hi Dave,
> > > > >
> > > >
> > > > + Lyude who has been hacking in this code recently
> > >
> > > gentle ping for the reviewers,
> > >
> > hi-actually yes, we should probably be using this instead of just dropping
> > this. Also, I didn't write this code originally I just refactored a bunch
> > of
> > it - Dave Airlied is the original author, but the original version of this
> > code was written ages ago. tbh, I think it's a safe bet to say that they
> > probably did mean to use this but forgot to and no one noticed until now.
>
> Hi,
>
> Any clue about how to use crc value ? Does it have to be checked
> against something else ?
> If crc are not matching what should we do of the data copied just before ?
We should be able to just take the CRC value from the sideband message and
then generate our own CRC value using the sideband message contents, and check
if the two are equal. If they aren't, something went wrong and we didn't
receive the message properly.
Now as to what we should do when we have CRC mismatches? That's a bit more
difficult. If you have access to the DP MST spec, I suppose a place to start
figuring that out would be checking if there's a way for us to request that a
branch device resend whatever message it sent previously. If there isn't, I
guess we should just print an error in dmesg (possibly with a hexdump of the
failed message as well) and not forward the message to the driver. Not sure of
any better way of handling it then that
>
> Benjamin
>
> > > Thanks,
> > > Benjamin
> > > > > Your are the original writer of this code, could you tell us if we
> > > > > can
> > > > > drop crc4
> > > > > ao if there is something else that I have misunderstood ?
> > > > >
> > > > > Thanks,
> > > > > Benjamin
> > > > >
> > > > > > BR,
> > > > > > Jani.
> > > > > >
> > > > > > > /* copy chunk into bigger msg */
> > > > > > > memcpy(&msg->msg[msg->curlen], msg->chunk, msg-
> > > > > > > > curchunk_len - 1);
> > > > > > > msg->curlen += msg->curchunk_len - 1;
> > > > > > > @@ -1014,7 +1011,7 @@ 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;
> > > > > > >
> > > > > > > @@ -1024,17 +1021,14 @@ 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_enum_path_resources(struct
> > > > > > > drm_dp_sideband_msg_tx
> > > > > > > *msg, int port_num)
> > > > > > > @@ -1048,7 +1042,7 @@ 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,
> > > > > > > +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)
> > > > > > > @@ -1064,10 +1058,9 @@ 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,
> > > > > > > +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;
> > > > > > > @@ -1080,7 +1073,6 @@ 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,
> > > > > > > @@ -1746,14 +1738,13 @@ 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)
> > > > > > > {
> > > > > > > - 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);
> > > > > > > @@ -1823,25 +1814,20 @@ 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(
> > > > > > > - mstb->mgr,
> > > > > > > - mstb->port_parent,
> > > > > > > - DP_GUID,
> > > > > > > - 16,
> > > > > > > - mstb->guid);
> > > > > > > + 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);
> > > > > > > + drm_dp_dpcd_write(mstb->mgr->aux,
> > > > > > > + DP_GUID,
> > > > > > > + mstb->guid,
> > > > > > > + 16);
> > > > > > > }
> > > > > > > }
> > > > > > > }
> > > > > > > @@ -2197,7 +2183,7 @@ 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;
> > > > > > >
> > > > > > > @@ -2206,8 +2192,6 @@ 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,
> > > > > > > @@ -2429,14 +2413,14 @@ 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);
> > > > > > >
> > > > > > > mstb->link_address_sent = true;
> > > > > > > drm_dp_queue_down_tx(mgr, txmsg);
> > > > > > > @@ -2478,7 +2462,6 @@ 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);
> > > > > > > @@ -2486,7 +2469,7 @@ 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);
> > > > > > >
> > > > > > > @@ -2569,7 +2552,7 @@ 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;
> > > > > > >
> > > > > > > @@ -2594,9 +2577,9 @@ 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);
> > > > > > >
> > > > > > > @@ -2625,7 +2608,7 @@ 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)
> > > > > > > @@ -2638,7 +2621,7 @@ 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);
> > > > > > > @@ -2858,7 +2841,6 @@ 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;
> > > > > > > @@ -2873,7 +2855,7 @@ 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);
> > > > > > > @@ -2911,7 +2893,6 @@ 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;
> > > > > > > @@ -2926,7 +2907,7 @@ 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);
> > > > > > > @@ -3149,7 +3130,7 @@ static bool drm_dp_get_one_sb_msg(struct
> > > > > > > drm_dp_mst_topology_mgr *mgr, bool up)
> > > > > > > {
> > > > > > > int len;
> > > > > > > u8 replyblock[32];
> > > > > > > - int replylen, origlen, curreply;
> > > > > > > + int replylen, curreply;
> > > > > > > int ret;
> > > > > > > struct drm_dp_sideband_msg_rx *msg;
> > > > > > > int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE :
> > > > > > > DP_SIDEBAND_MSG_DOWN_REP_BASE;
> > > > > > > @@ -3169,7 +3150,6 @@ static bool drm_dp_get_one_sb_msg(struct
> > > > > > > drm_dp_mst_topology_mgr *mgr, bool up)
> > > > > > > }
> > > > > > > replylen = msg->curchunk_len + msg->curchunk_hdrlen;
> > > > > > >
> > > > > > > - origlen = replylen;
> > > > > > > replylen -= len;
> > > > > > > curreply = len;
> > > > > > > while (replylen > 0) {
> > > > > > > @@ -3961,17 +3941,16 @@ void drm_dp_mst_dump_topology(struct
> > > > > > > seq_file *m,
> > > > > > > mutex_lock(&mgr->lock);
> > > > > > > if (mgr->mst_primary) {
> > > > > > > u8 buf[DP_PAYLOAD_TABLE_SIZE];
> > > > > > > - int ret;
> > > > > > >
> > > > > > > - ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, buf,
> > > > > > > DP_RECEIVER_CAP_SIZE);
> > > > > > > + drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, buf,
> > > > > > > DP_RECEIVER_CAP_SIZE);
> > > > > > > seq_printf(m, "dpcd: %*ph\n",
> > > > > > > DP_RECEIVER_CAP_SIZE,
> > > > > > > buf);
> > > > > > > - ret = drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf,
> > > > > > > 2);
> > > > > > > + drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf, 2);
> > > > > > > seq_printf(m, "faux/mst: %*ph\n", 2, buf);
> > > > > > > - ret = drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL,
> > > > > > > buf,
> > > > > > > 1);
> > > > > > > + drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL, buf, 1);
> > > > > > > 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);
> > > > > > > + drm_dp_dpcd_read(mgr->aux, DP_BRANCH_OUI, buf,
> > > > > > > DP_BRANCH_OUI_HEADER_SIZE);
> > > > > > > seq_printf(m, "branch oui: %*phN devid: ", 3,
> > > > > > > buf);
> > > > > > > for (i = 0x3; i < 0x8 && buf[i]; i++)
> > > > > > > seq_printf(m, "%c", buf[i]);
> > > > > >
> > > > > > --
> > > > > > Jani Nikula, Intel Open Source Graphics Center
> > > > > > _______________________________________________
> > > > > > dri-devel mailing list
> > > > > > dri-devel at lists.freedesktop.org
> > > > > > https://lists.freedesktop.org/mailman/listinfo/dri-devel
> > --
> > Cheers,
> > Lyude Paul
> >
--
Cheers,
Lyude Paul
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