From: Michael Strauss <michael.strauss@xxxxxxx>
commit 2ec6c7f802332d1eff16f03e7c757f1543ee1183 upstream.
[WHY]
New register field added in DP2.1 SCR, needed for auxless ALPM
[HOW]
Echo value read from 0xF0007 back to sink
Reviewed-by: Wenjing Liu <wenjing.liu@xxxxxxx>
Cc: Mario Limonciello <mario.limonciello@xxxxxxx>
Cc: Alex Deucher <alexander.deucher@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Alex Hung <alex.hung@xxxxxxx>
Signed-off-by: Michael Strauss <michael.strauss@xxxxxxx>
Tested-by: Daniel Wheeler <daniel.wheeler@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c | 10 +++++++++-
drivers/gpu/drm/amd/display/include/dpcd_defs.h | 5 +++++
2 files changed, 14 insertions(+), 1 deletion(-)
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
@@ -1590,9 +1590,17 @@ static bool retrieve_link_cap(struct dc_
return false;
}
- if (dp_is_lttpr_present(link))
+ if (dp_is_lttpr_present(link)) {
configure_lttpr_mode_transparent(link);
+ // Echo TOTAL_LTTPR_CNT back downstream
+ core_link_write_dpcd(
+ link,
+ DP_TOTAL_LTTPR_CNT,
+ &link->dpcd_caps.lttpr_caps.phy_repeater_cnt,
+ sizeof(link->dpcd_caps.lttpr_caps.phy_repeater_cnt));
+ }
+
/* Read DP tunneling information. */
status = dpcd_get_tunneling_device_data(link);
--- a/drivers/gpu/drm/amd/display/include/dpcd_defs.h
+++ b/drivers/gpu/drm/amd/display/include/dpcd_defs.h
@@ -177,4 +177,9 @@ enum dpcd_psr_sink_states {
#define DP_SINK_PR_PIXEL_DEVIATION_PER_LINE 0x379
#define DP_SINK_PR_MAX_NUMBER_OF_DEVIATION_LINE 0x37A
+/* Remove once drm_dp_helper.h is updated upstream */
+#ifndef DP_TOTAL_LTTPR_CNT
+#define DP_TOTAL_LTTPR_CNT 0xF000A /* 2.1 */
+#endif
+
#endif /* __DAL_DPCD_DEFS_H__ */
Patches currently in stable-queue which might be from michael.strauss@xxxxxxx are
queue-6.9/drm-amd-display-send-dp_total_lttpr_cnt-during-detection-if-lttpr-is-present.patch
