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authorLyude Paul <lyude@redhat.com>2020-04-24 15:07:22 -0400
committerLyude Paul <lyude@redhat.com>2020-04-27 12:50:18 -0400
commitdbc05ae3867628abce5619bfab868a43818bdb0d (patch)
tree375deb3ceac9799a5d30133d755bb7df1238ae87 /drivers/gpu/drm/drm_dp_mst_topology.c
parenta5bff92eaac45bdf6221badf9505c26792fdf99e (diff)
drm/dp_mst: Fix drm_dp_send_dpcd_write() return code
drm_dp_mst_wait_tx_reply() returns > 1 if time elapsed in wait_event_timeout() before check_txmsg_state(mgr, txmsg) evaluated to true. However, we make the mistake of returning this time from drm_dp_send_dpcd_write() on success instead of returning the number of bytes written - causing spontaneous failures during link probing: [drm:drm_dp_send_link_address [drm_kms_helper]] *ERROR* GUID check on 10:01 failed: 3975 Yikes! So, fix this by returning the number of bytes written on success instead. Signed-off-by: Lyude Paul <lyude@redhat.com> Fixes: cb897542c6d2 ("drm/dp_mst: Fix W=1 warnings") Cc: Benjamin Gaignard <benjamin.gaignard@st.com> Cc: Sean Paul <sean@poorly.run> Acked-by: Alex Deucher <alexander.deucher@amd.com> Reviewed-by: Sean Paul <sean@poorly.run> Link: https://patchwork.freedesktop.org/patch/msgid/20200424190722.775284-1-lyude@redhat.com
Diffstat (limited to 'drivers/gpu/drm/drm_dp_mst_topology.c')
-rw-r--r--drivers/gpu/drm/drm_dp_mst_topology.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 283615e44838..9d89ebf3a749 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -3442,8 +3442,12 @@ static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
drm_dp_queue_down_tx(mgr, txmsg);
ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
- if (ret > 0 && txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
- ret = -EIO;
+ if (ret > 0) {
+ if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
+ ret = -EIO;
+ else
+ ret = size;
+ }
kfree(txmsg);
fail_put: