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 <[email protected]> Fixes: cb897542c6d2 ("drm/dp_mst: Fix W=1 warnings") Cc: Benjamin Gaignard <[email protected]> Cc: Sean Paul <[email protected]> Acked-by: Alex Deucher <[email protected]> Reviewed-by: Sean Paul <[email protected]> Link: https://patchwork.freedesktop.org/patch/msgid/[email protected] --- drivers/gpu/drm/drm_dp_mst_topology.c | 8 ++++++-- 1 file 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 77f6d2cbefac..46920e9be9e6 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -3438,8 +3438,12 @@ 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: -- 2.25.3 _______________________________________________ kernel mailing list -- [email protected] To unsubscribe send an email to [email protected] Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/[email protected]
