diff options
| author |   Timur Kristóf <timur.kristof@gmail.com> | 2026-05-29 11:09:09 +0200 |
|---|---|---|
| committer |   Alex Deucher <alexander.deucher@amd.com> | 2026-07-15 09:15:37 -0400 |
| commit | 871ceb853841bcaa4e6cec3723b16c4887a760be (patch) | |
| tree | 6db179fcec0aae084b4288fd03e380ebff0d505d | |
| parent | drm/amd/display: Fix preferred link rate for NUTMEG (diff) | |
drm/amd/display: Add dp_skip_rbr flag for NUTMEG
No functional changes. Just clean up a conceptual mismatch.
Based on feedback on the NUTMEG code in DC, the
preferred_link_setting is meant to force the DP link to a
specific setting, meaning both the link rate and lane count
should be locked to an exact value. What NUTMEG needs is
a lower bound on the link rate, which is not the same concept.
Implement this as a HW workaround flag instead.
Suggested-by: Wenjing Liu <wenjing.liu@amd.com>
Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
| -rw-r--r-- | drivers/gpu/drm/amd/display/dc/dc.h | 2 | ||||
| -rw-r--r-- | drivers/gpu/drm/amd/display/dc/link/link_detection.c | 2 | ||||
| -rw-r--r-- | drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c | 6 |
3 files changed, 6 insertions, 4 deletions
diff --git a/drivers/gpu/drm/amd/display/dc/dc.h b/drivers/gpu/drm/amd/display/dc/dc.h index c78fdfc0ef4b..a10ee711668e 100644 --- a/drivers/gpu/drm/amd/display/dc/dc.h +++ b/drivers/gpu/drm/amd/display/dc/dc.h @@ -1936,6 +1936,8 @@ struct dc_scratch_space { bool dp_skip_DID2; bool dp_skip_reset_segment; bool dp_skip_fs_144hz; + /* Some DP bridges don't work with RBR and must use HBR. */ + bool dp_skip_rbr; bool dp_mot_reset_segment; /* Some USB4 docks do not handle turning off MST DSC once it has been enabled. */ bool dpia_mst_dsc_always_on; diff --git a/drivers/gpu/drm/amd/display/dc/link/link_detection.c b/drivers/gpu/drm/amd/display/dc/link/link_detection.c index 2abe9d3a68d5..4f18b668340c 100644 --- a/drivers/gpu/drm/amd/display/dc/link/link_detection.c +++ b/drivers/gpu/drm/amd/display/dc/link/link_detection.c @@ -646,7 +646,7 @@ static bool detect_dp(struct dc_link *link, link->dpcd_caps.sink_count.bits.SINK_COUNT = 1; /* NUTMEG requires that we use HBR, doesn't work with RBR. */ if (link->dpcd_caps.branch_dev_id == DP_BRANCH_DEVICE_ID_00001A) - link->preferred_link_setting.link_rate = LINK_RATE_HIGH; + link->wa_flags.dp_skip_rbr = true; } return true; diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c index 5d3b5266005d..24e3bbec15ff 100644 --- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c +++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c @@ -756,9 +756,9 @@ static bool decide_dp_link_settings(struct dc_link *link, struct dc_link_setting if (req_bw > dp_link_bandwidth_kbps(link, &link->verified_link_cap)) return false; - if (link->preferred_link_setting.link_rate != LINK_RATE_UNKNOWN) { - initial_link_setting.link_rate = link->preferred_link_setting.link_rate; - current_link_setting.link_rate = link->preferred_link_setting.link_rate; + if (link->wa_flags.dp_skip_rbr) { + initial_link_setting.link_rate = LINK_RATE_HIGH; + current_link_setting.link_rate = LINK_RATE_HIGH; } /* search for the minimum link setting that: |