diff options
| author | Timur Kristóf <timur.kristof@gmail.com> | 2026-05-29 11:09:09 +0200 |
|---|---|---|
| committer | Alex Deucher <alexander.deucher@amd.com> | 2026-07-17 17:37:28 -0400 |
| commit | e39b7cf5c62e027af166772e46382356ecb45c36 (patch) | |
| tree | 972d30a2dbf6589710897c4fc2fa33a253c5d0f3 /drivers/gpu | |
| parent | 9fb646bc4d87f62bcbf0a7ea326430eb802c475c (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>
(cherry picked from commit 871ceb853841bcaa4e6cec3723b16c4887a760be)
Cc: stable@vger.kernel.org
Diffstat (limited to 'drivers/gpu')
| -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 82d02ebbd829..ebdcbfa7db80 100644 --- a/drivers/gpu/drm/amd/display/dc/dc.h +++ b/drivers/gpu/drm/amd/display/dc/dc.h @@ -1815,6 +1815,8 @@ 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 7d8951fecd57..29dbb5e410d8 100644 --- a/drivers/gpu/drm/amd/display/dc/link/link_detection.c +++ b/drivers/gpu/drm/amd/display/dc/link/link_detection.c @@ -623,7 +623,7 @@ 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 4079f128bade..1cd17a0272bc 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 @@ -750,9 +750,9 @@ 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: |