From: Ilya Bakoulin <ilya.bakoulin@xxxxxxx>
[Why]
This display doesn't properly indicate link loss through DPCD bits such
as CR_DONE / CHANNEL_EQ_DONE / SYMBOL_LOCKED / INTERLANE_ALIGN_DONE,
which all remain set.
In addition, DPCD200Eh doesn't match the value of DPCD204h in all cases.
For these reasons, we can miss re-training the link, since we don't
properly detect link loss with this display.
[Why]
Add display-specific workaround to read DPCD204h, so that we can detect
link loss based on 128b132b-specific status bits in this register.
Reviewed-by: Wenjing Liu <wenjing.liu@xxxxxxx>
Acked-by: Rodrigo Siqueira <rodrigo.siqueira@xxxxxxx>
Signed-off-by: Ilya Bakoulin <ilya.bakoulin@xxxxxxx>
---
drivers/gpu/drm/amd/display/dc/dc.h | 1 +
.../dc/link/protocols/link_dp_irq_handler.c | 26 +++++++++++++++++++
2 files changed, 27 insertions(+)
diff --git a/drivers/gpu/drm/amd/display/dc/dc.h b/drivers/gpu/drm/amd/display/dc/dc.h
index ea0b78ef351d..24f580bdac6a 100644
--- a/drivers/gpu/drm/amd/display/dc/dc.h
+++ b/drivers/gpu/drm/amd/display/dc/dc.h
@@ -1525,6 +1525,7 @@ struct dc_link {
bool dpia_forced_tbt3_mode;
bool dongle_mode_timing_override;
bool blank_stream_on_ocs_change;
+ bool read_dpcd204h_on_irq_hpd;
} wa_flags;
struct link_mst_stream_allocation_table mst_stream_alloc_table;
diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_irq_handler.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_irq_handler.c
index b1b11eb0f9bb..ef8739df91bc 100644
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_irq_handler.c
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_irq_handler.c
@@ -208,6 +208,25 @@ void dp_handle_link_loss(struct dc_link *link)
}
}
+static void read_dpcd204h_on_irq_hpd(struct dc_link *link, union hpd_irq_data *irq_data)
+{
+ enum dc_status retval;
+ union lane_align_status_updated dpcd_lane_status_updated;
+
+ retval = core_link_read_dpcd(
+ link,
+ DP_LANE_ALIGN_STATUS_UPDATED,
+ &dpcd_lane_status_updated.raw,
+ sizeof(union lane_align_status_updated));
+
+ if (retval == DC_OK) {
+ irq_data->bytes.lane_status_updated.bits.EQ_INTERLANE_ALIGN_DONE_128b_132b =
+ dpcd_lane_status_updated.bits.EQ_INTERLANE_ALIGN_DONE_128b_132b;
+ irq_data->bytes.lane_status_updated.bits.CDS_INTERLANE_ALIGN_DONE_128b_132b =
+ dpcd_lane_status_updated.bits.CDS_INTERLANE_ALIGN_DONE_128b_132b;
+ }
+}
+
enum dc_status dp_read_hpd_rx_irq_data(
struct dc_link *link,
union hpd_irq_data *irq_data)
@@ -249,6 +268,13 @@ enum dc_status dp_read_hpd_rx_irq_data(
irq_data->bytes.lane23_status.raw = tmp[DP_LANE2_3_STATUS_ESI - DP_SINK_COUNT_ESI];
irq_data->bytes.lane_status_updated.raw = tmp[DP_LANE_ALIGN_STATUS_UPDATED_ESI - DP_SINK_COUNT_ESI];
irq_data->bytes.sink_status.raw = tmp[DP_SINK_STATUS_ESI - DP_SINK_COUNT_ESI];
+
+ /*
+ * This display doesn't have correct values in DPCD200Eh.
+ * Read and check DPCD204h instead.
+ */
+ if (link->wa_flags.read_dpcd204h_on_irq_hpd)
+ read_dpcd204h_on_irq_hpd(link, irq_data);
}
return retval;
--
2.39.2
