From: Zhan Liu <zhan....@amd.com>
[Why]
eDP version and DPCD revision are different. Per VESA
spec, "The DPCD revision for eDP v1.4 is 13h".
SUPPORTED_LINK_RATES is valid since eDP v1.4 (DPCD_REV_13).
[How]
Correct DPCD_REV for eDP v1.4.
Signed-off-by: Zhan Liu <zhan....@amd.com>
Reviewed-by: Nikola Cornij <nikola.cor...@amd.com>
Acked-by: Stylon Wang <stylon.w...@amd.com>
---
drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
index e860d7cd4fc6..9e08410bfdfd 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
@@ -2595,7 +2595,11 @@ bool decide_edp_link_settings(struct dc_link *link,
struct dc_link_settings *lin
struct dc_link_settings current_link_setting;
uint32_t link_bw;
- if (link->dpcd_caps.dpcd_rev.raw < DPCD_REV_14 ||
+ /*
+ * edp_supported_link_rates_count is only valid for eDP v1.4 or higher.
+ * Per VESA eDP spec, "The DPCD revision for eDP v1.4 is 13h"
+ */
+ if (link->dpcd_caps.dpcd_rev.raw < DPCD_REV_13 ||
link->dpcd_caps.edp_supported_link_rates_count == 0) {
*link_setting = link->verified_link_cap;
return true;
@@ -4018,7 +4022,11 @@ void detect_edp_sink_caps(struct dc_link *link)
link->dpcd_caps.edp_supported_link_rates_count = 0;
memset(supported_link_rates, 0, sizeof(supported_link_rates));
- if (link->dpcd_caps.dpcd_rev.raw >= DPCD_REV_14 &&
+ /*
+ * edp_supported_link_rates_count is only valid for eDP v1.4 or higher.
+ * Per VESA eDP spec, "The DPCD revision for eDP v1.4 is 13h"
+ */
+ if (link->dpcd_caps.dpcd_rev.raw >= DPCD_REV_13 &&
(link->dc->debug.optimize_edp_link_rate ||
link->reported_link_cap.link_rate ==
LINK_RATE_UNKNOWN)) {
// Read DPCD 00010h - 0001Fh 16 bytes at one shot
--
2.25.1
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