From: Wesley Chalmers <Wesley.Chalmers@xxxxxxx>
[ Upstream commit 53c81fc7875bc2dca358485dac3999e14ec91a00 ]
[WHY]
Some panels return a link rate of 0 (unknown) in DPCD 0. In this case,
an appropriate mode cannot be set, and certain panels will show
corruption as they are forced to use a mode they do not support.
[HOW]
Read DPCD 10 in the case where supported link rate from DPCD 0 is
unknown, and pass that value on to the reported link rate.
This re-introduces behaviour present in previous versions that appears
to have been accidentally removed.
Signed-off-by: Wesley Chalmers <Wesley.Chalmers@xxxxxxx>
Reviewed-by: Anthony Koo <Anthony.Koo@xxxxxxx>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 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 1ee544a32ebb..253311864cdd 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
@@ -1624,8 +1624,7 @@ static bool decide_edp_link_settings(struct dc_link *link, struct dc_link_settin
uint32_t link_bw;
if (link->dpcd_caps.dpcd_rev.raw < DPCD_REV_14 ||
- link->dpcd_caps.edp_supported_link_rates_count == 0 ||
- link->dc->config.optimize_edp_link_rate == false) {
+ link->dpcd_caps.edp_supported_link_rates_count == 0) {
*link_setting = link->verified_link_cap;
return true;
}
@@ -2597,7 +2596,8 @@ void detect_edp_sink_caps(struct dc_link *link)
memset(supported_link_rates, 0, sizeof(supported_link_rates));
if (link->dpcd_caps.dpcd_rev.raw >= DPCD_REV_14 &&
- link->dc->config.optimize_edp_link_rate) {
+ (link->dc->config.optimize_edp_link_rate ||
+ link->reported_link_cap.link_rate == LINK_RATE_UNKNOWN)) {
// Read DPCD 00010h - 0001Fh 16 bytes at one shot
core_link_read_dpcd(link, DP_SUPPORTED_LINK_RATES,
supported_link_rates, sizeof(supported_link_rates));
@@ -2612,6 +2612,9 @@ void detect_edp_sink_caps(struct dc_link *link)
link_rate = linkRateInKHzToLinkRateMultiplier(link_rate_in_khz);
link->dpcd_caps.edp_supported_link_rates[link->dpcd_caps.edp_supported_link_rates_count] = link_rate;
link->dpcd_caps.edp_supported_link_rates_count++;
+
+ if (link->reported_link_cap.link_rate < link_rate)
+ link->reported_link_cap.link_rate = link_rate;
}
}
}
--
2.20.1
