From: Harmanprit Tatla <harmanprit.tatla@xxxxxxx>
[ Upstream commit 5b25e5f1a97284020abee7348427f89abdb674e8 ]
[Why]
There are certain MST displays (i.e. Dell P2715Q)
that although have the MST feature set to off may still
report it is a branch device and a non-zero
value for downstream port present.
This can lead to us incorrectly classifying a
dp dongle connection as being active and
disabling the audio endpoint for the display.
[How]
Modified the placement and
condition used to assign
the is_branch_dev bit.
Signed-off-by: Harmanprit Tatla <harmanprit.tatla@xxxxxxx>
Reviewed-by: Aric Cyr <aric.cyr@xxxxxxx>
Acked-by: Anthony Koo <Anthony.Koo@xxxxxxx>
Acked-by: Leo Li <sunpeng.li@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, 8 insertions(+), 1 deletion(-)
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 253311864cdd5..966aa3b754c5b 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
@@ -2218,11 +2218,18 @@ static void get_active_converter_info(
link->dpcd_caps.dongle_type = DISPLAY_DONGLE_NONE;
ddc_service_set_dongle_type(link->ddc,
link->dpcd_caps.dongle_type);
+ link->dpcd_caps.is_branch_dev = false;
return;
}
/* DPCD 0x5 bit 0 = 1, it indicate it's branch device */
- link->dpcd_caps.is_branch_dev = ds_port.fields.PORT_PRESENT;
+ if (ds_port.fields.PORT_TYPE == DOWNSTREAM_DP) {
+ link->dpcd_caps.is_branch_dev = false;
+ }
+
+ else {
+ link->dpcd_caps.is_branch_dev = ds_port.fields.PORT_PRESENT;
+ }
switch (ds_port.fields.PORT_TYPE) {
case DOWNSTREAM_VGA:
--
2.20.1
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