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drm/amd/display: Fix wrong resolution with DP/VGA adapter

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[Why]
Hotplugging the VGA side of some DP/VGA adapters caused the display to
light up with the wrong (non-native) resolution.

This is caused by the adapter misbehaving by reporting the wrong number
of downstream ports when the VGA side is unplugged (reports 1 instead of
0), but only if the SINK_COUNT DPCD register is read more than once.

[How]
To work around the adapter behavior, remove the sink if link is
detected, but EDID cannot be read.

Reviewed-by: Wenjing Liu <Wenjing.Liu@amd.com>
Acked-by: Solomon Chiu <solomon.chiu@amd.com>
Signed-off-by: Ilya <Ilya.Bakoulin@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Ilya 2022-02-10 11:09:33 -05:00 committed by Alex Deucher
parent 3e6084aee0
commit 10a9accd48
2 changed files with 19 additions and 0 deletions
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16
drivers/gpu/drm/amd/display/dc/core/dc_link.c
View File

@ -1197,6 +1197,22 @@ static bool detect_link_and_local_sink(struct dc_link *link,
return false;
}
if (link->type == dc_connection_sst_branch &&
link->dpcd_caps.dongle_type ==
DISPLAY_DONGLE_DP_VGA_CONVERTER &&
reason == DETECT_REASON_HPDRX) {
/* Abort detection for DP-VGA adapters when EDID
* can't be read and detection reason is VGA-side
* hotplug
*/
if (prev_sink)
dc_sink_release(prev_sink);
link_disconnect_sink(link);
return true;
}
break;
default:
break;

3
drivers/gpu/drm/amd/display/dc/core/dc_link_ddc.c
View File

@ -298,6 +298,9 @@ static uint32_t defer_delay_converter_wa(
if (link->dpcd_caps.dongle_type == DISPLAY_DONGLE_DP_VGA_CONVERTER &&
link->dpcd_caps.branch_dev_id == DP_BRANCH_DEVICE_ID_0080E1 &&
(link->dpcd_caps.branch_fw_revision[0] < 0x01 ||
(link->dpcd_caps.branch_fw_revision[0] == 0x01 &&
link->dpcd_caps.branch_fw_revision[1] < 0x40)) &&
!memcmp(link->dpcd_caps.branch_dev_name,
DP_VGA_DONGLE_BRANCH_DEV_NAME,
sizeof(link->dpcd_caps.branch_dev_name)))