From: abdoulaye berthe <abdoulaye.ber...@amd.com>
[Why]
LTTPR was introduced after DP1.2. Reading LTTPR registers 0xFXXXX
on some DP 1.2 display is causing an unexpected behavior.
[How]
Make sure that we don't read any lttpr registers on 1.2 displays.
Signed-off-by: abdoulaye berthe <abdoulaye.ber...@amd.com>
Reviewed-by: Aric Cyr <aric....@amd.com>
---
drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 5 +++--
1 file changed, 3 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 2a89f90ef7a7..1e4480f3bd3c 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
@@ -2759,9 +2759,10 @@ static bool retrieve_link_cap(struct dc_link *link)
/* Set default timeout to 3.2ms and read LTTPR capabilities */
bool ext_timeout_support = link->dc->caps.extended_aux_timeout_support
&&
!link->dc->config.disable_extended_timeout_support;
+ link->is_lttpr_mode_transparent = true;
+
if (ext_timeout_support) {
status = dc_link_aux_configure_timeout(link->ddc,
LINK_AUX_DEFAULT_EXTENDED_TIMEOUT_PERIOD);
- link->is_lttpr_mode_transparent = true;
}
memset(dpcd_data, '\0', sizeof(dpcd_data));
@@ -2796,7 +2797,7 @@ static bool retrieve_link_cap(struct dc_link *link)
return false;
}
- if (ext_timeout_support) {
+ if (ext_timeout_support && link->dpcd_caps.dpcd_rev.raw >= 0x14) {
status = core_link_read_dpcd(
link,
DP_PHY_REPEATER_CNT,
--
2.17.1
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