6.6-stable review patch. If anyone has any objections, please let me know.
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From: Michael Strauss michael.strauss@amd.com
[ Upstream commit e3419e1e44b87d4176fb98679a77301b1ca40f63 ]
[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@amd.com Signed-off-by: Michael Strauss michael.strauss@amd.com Signed-off-by: Ivan Lipski ivan.lipski@amd.com Tested-by: Daniel Wheeler daniel.wheeler@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Signed-off-by: Sasha Levin sashal@kernel.org --- .../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 51e88efee11e4..08c2f11724140 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 @@ -974,14 +974,19 @@ void repeater_training_done(struct dc_link *link, uint32_t offset) static void dpcd_exit_training_mode(struct dc_link *link, enum dp_link_encoding encoding) { 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 */ dpcd_set_training_pattern(link, DP_TRAINING_PATTERN_VIDEOIDLE);
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;