@@ -1799,17 +1799,27 @@ static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
return 0;
}
-static int drm_dp_get_vc_payload_bw(int dp_link_bw, int dp_link_count)
+static bool drm_dp_get_vc_payload_bw(int dp_link_bw,
+ int dp_link_count,
+ int *out)
{
switch (dp_link_bw) {
+ default:
+ DRM_DEBUG_KMS("invalid link bandwidth in DPCD: %x (link count: %d)\n",
+ dp_link_bw, dp_link_count);
+ return false;
+
case DP_LINK_BW_1_62:
- return 3 * dp_link_count;
+ *out = 3 * dp_link_count;
+ break;
case DP_LINK_BW_2_7:
- return 5 * dp_link_count;
+ *out = 5 * dp_link_count;
+ break;
case DP_LINK_BW_5_4:
- return 10 * dp_link_count;
+ *out = 10 * dp_link_count;
+ break;
}
- BUG();
+ return true;
}
/**
@@ -1841,7 +1851,13 @@ int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms
goto out_unlock;
}
- mgr->pbn_div = drm_dp_get_vc_payload_bw(mgr->dpcd[1], mgr->dpcd[2] & DP_MAX_LANE_COUNT_MASK);
+ if (!drm_dp_get_vc_payload_bw(mgr->dpcd[1],
+ mgr->dpcd[2] & DP_MAX_LANE_COUNT_MASK,
+ &mgr->pbn_div)) {
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+
mgr->total_pbn = 2560;
mgr->total_slots = DIV_ROUND_UP(mgr->total_pbn, mgr->pbn_div);
mgr->avail_slots = mgr->total_slots;
Don't BUG out if the link reports an invalid (or plain unknown) bandwidth value, but report the failure and fail gracefully. Fixes a trivial compiler warning in case the BUG is ever compiled away. Link: http://lkml.kernel.org/p/1415785566-12758-1-git-send-email-geert@linux-m68k.org Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Dave Airlie <airlied@redhat.com> --- drivers/gpu/drm/drm_dp_mst_topology.c | 28 ++++++++++++++++++++++------ 1 file changed, 22 insertions(+), 6 deletions(-)