[PATCH 09/32] drm/amd/display: Add retires when read DPCD

[Zaeem Mohamed]

From: Joan Lee <joan.lee at amd.com>

[why & how]
Sometimes read DPCD return fail while result not retrieved yet. Add
retries mechanism in Replay handle hpd irq to get real result.

Reviewed-by: Jerry Zuo <jerry.zuo at amd.com>
Acked-by: Zaeem Mohamed <zaeem.mohamed at amd.com>
Signed-off-by: Joan Lee <joan.lee at amd.com>
---
 .../dc/link/protocols/link_dp_irq_handler.c   | 26 ++++++++++++++-----
 1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_irq_handler.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_irq_handler.c
index 659b8064d361..5f087e930cb6 100644
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_irq_handler.c
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_irq_handler.c
@@ -189,16 +189,30 @@ static void handle_hpd_irq_replay_sink(struct dc_link *link)
 	union dpcd_replay_configuration replay_configuration = {0};
 	/*AMD Replay version reuse DP_PSR_ERROR_STATUS for REPLAY_ERROR status.*/
 	union psr_error_status replay_error_status = {0};
+	bool ret = false;
+	int retries = 0;
 
 	if (!link->replay_settings.replay_feature_enabled)
 		return;
 
-	dm_helpers_dp_read_dpcd(
-		link->ctx,
-		link,
-		DP_SINK_PR_REPLAY_STATUS,
-		&replay_configuration.raw,
-		sizeof(replay_configuration.raw));
+	while (retries < 10) {
+		ret = dm_helpers_dp_read_dpcd(
+			link->ctx,
+			link,
+			DP_SINK_PR_REPLAY_STATUS,
+			&replay_configuration.raw,
+			sizeof(replay_configuration.raw));
+
+		if (ret)
+			break;
+
+		retries++;
+	}
+
+	if (!ret)
+		DC_LOG_WARNING("[%s][%d] DPCD read addr.0x%x failed with %d retries\n",
+					__func__, __LINE__,
+					DP_SINK_PR_REPLAY_STATUS, retries);
 
 	dm_helpers_dp_read_dpcd(
 		link->ctx,
-- 
2.34.1