[PATCH 19/25] drm/amd/display: Increase AUX Intra-Hop Done Max Wait Duration

[IVAN.LIPSKI at amd.com]

From: Michael Strauss <michael.strauss at amd.com>

[WHY]
In the worst case, AUX intra-hop done can take hundreds of milliseconds as
each retimer in a link might have to wait a full AUX_RD_INTERVAL to send
LT abort downstream.

[HOW]
Wait 300ms for each retimer in a link to allow time to propagate a LT abort
without infinitely waiting on intra-hop done.
For no-retimer case, keep the max duration at 10ms.

Reviewed-by: Wenjing Liu <wenjing.liu at amd.com>
Signed-off-by: Michael Strauss <michael.strauss at amd.com>
Signed-off-by: Ivan Lipski <ivan.lipski at amd.com>
---
 .../drm/amd/display/dc/link/protocols/link_dp_training.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c
index 2dc1a660e504..134093ce5a8e 100644
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c
@@ -1018,7 +1018,12 @@ static enum link_training_result dpcd_exit_training_mode(struct dc_link *link, e
 {
 	enum dc_status status;
 	uint8_t sink_status = 0;
-	uint8_t i;
+	uint32_t i;
+	uint8_t lttpr_count = dp_parse_lttpr_repeater_count(link->dpcd_caps.lttpr_caps.phy_repeater_cnt);
+	uint32_t intra_hop_disable_time_ms = (lttpr_count > 0 ? lttpr_count * 300 : 10);
+
+	// Each hop could theoretically take over 256ms (max 128b/132b AUX RD INTERVAL)
+	// To be safe, allow 300ms per LTTPR and 10ms for no LTTPR case
 
 	/* clear training pattern set */
 	status = dpcd_set_training_pattern(link, DP_TRAINING_PATTERN_VIDEOIDLE);
@@ -1028,7 +1033,7 @@ static enum link_training_result dpcd_exit_training_mode(struct dc_link *link, e
 
 	if (encoding == DP_128b_132b_ENCODING) {
 		/* poll for intra-hop disable */
-		for (i = 0; i < 10; i++) {
+		for (i = 0; i < intra_hop_disable_time_ms; i++) {
 			if ((core_link_read_dpcd(link, DP_SINK_STATUS, &sink_status, 1) == DC_OK) &&
 					(sink_status & DP_INTRA_HOP_AUX_REPLY_INDICATION) == 0)
 				break;
-- 
2.43.0