thunderbolt: Calculate DisplayPort tunnel bandwidth after DPRX capabilities read

[ Upstream commit ccd845021147dc8257a05ed8f5a7f9c61a9101e3 ]

According to USB4 Connection Manager guide, after DisplayPort tunnel was
setup, the DPRX capabilities read is performed by the DPTX. According to
VESA spec, this shall be completed within 5 seconds after the DisplayPort
tunnel was setup. Hence, if the bit: DPRX Capabilities Read Done, was
not set to '1' by this time, we timeout and fail calculating DisplayPort
tunnel consumed bandwidth.

Signed-off-by: Gil Fine <gil.fine@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/thunderbolt/tunnel.c b/drivers/thunderbolt/tunnel.c
index 6fffb2c82d3d1332a9de5005b7a67099ef5d8582..4f09216b70f903e99154a65d9b712837d5fa5c21 100644 (file)
--- a/drivers/thunderbolt/tunnel.c
+++ b/drivers/thunderbolt/tunnel.c
@@ -1196,17 +1196,13 @@ static int tb_dp_consumed_bandwidth(struct tb_tunnel *tunnel, int *consumed_up,
                /*
                 * Then see if the DPRX negotiation is ready and if yes
                 * return that bandwidth (it may be smaller than the
-                * reduced one). Otherwise return the remote (possibly
-                * reduced) caps.
+                * reduced one). According to VESA spec, the DPRX
+                * negotiation shall compete in 5 seconds after tunnel
+                * established. We give it 100ms extra just in case.
                 */
-               ret = tb_dp_wait_dprx(tunnel, 150);
-               if (ret) {
-                       if (ret == -ETIMEDOUT)
-                               ret = tb_dp_read_cap(tunnel, DP_REMOTE_CAP,
-                                                    &rate, &lanes);
-                       if (ret)
-                               return ret;
-               }
+               ret = tb_dp_wait_dprx(tunnel, 5100);
+               if (ret)
+                       return ret;
                ret = tb_dp_read_cap(tunnel, DP_COMMON_CAP, &rate, &lanes);
                if (ret)
                        return ret;