From: Wesley Chalmers <Wesley.Chalmers@xxxxxxx>
[WHY]
A new SCR for the DP2.0 spec requires that LTTPR caps be the first thing
read from DPCD upon hotplug.
Signed-off-by: Wesley Chalmers <Wesley.Chalmers@xxxxxxx>
Reviewed-by: Jun Lei <Jun.Lei@xxxxxxx>
Acked-by: Anson Jacob <Anson.Jacob@xxxxxxx>
---
.../gpu/drm/amd/display/dc/core/dc_link_dp.c | 65 ++++++++++---------
1 file changed, 33 insertions(+), 32 deletions(-)
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 7024589791fe..0e2741cd5f26 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
@@ -3660,38 +3660,6 @@ static bool retrieve_link_cap(struct dc_link *link)
dc_link_aux_try_to_configure_timeout(link->ddc,
LINK_AUX_DEFAULT_LTTPR_TIMEOUT_PERIOD);
- status = core_link_read_dpcd(link, DP_SET_POWER,
- &dpcd_power_state, sizeof(dpcd_power_state));
-
- /* Delay 1 ms if AUX CH is in power down state. Based on spec
- * section 2.3.1.2, if AUX CH may be powered down due to
- * write to DPCD 600h = 2. Sink AUX CH is monitoring differential
- * signal and may need up to 1 ms before being able to reply.
- */
- if (status != DC_OK || dpcd_power_state == DP_SET_POWER_D3)
- udelay(1000);
-
- dpcd_set_source_specific_data(link);
- /* Sink may need to configure internals based on vendor, so allow some
- * time before proceeding with possibly vendor specific transactions
- */
- msleep(post_oui_delay);
-
- for (i = 0; i < read_dpcd_retry_cnt; i++) {
- status = core_link_read_dpcd(
- link,
- DP_DPCD_REV,
- dpcd_data,
- sizeof(dpcd_data));
- if (status == DC_OK)
- break;
- }
-
- if (status != DC_OK) {
- dm_error("%s: Read dpcd data failed.\n", __func__);
- return false;
- }
-
/* Query BIOS to determine if LTTPR functionality is forced on by system */
if (bios->funcs->get_lttpr_caps) {
enum bp_result bp_query_result;
@@ -3778,6 +3746,39 @@ static bool retrieve_link_cap(struct dc_link *link)
dc_link_aux_try_to_configure_timeout(link->ddc, LINK_AUX_DEFAULT_TIMEOUT_PERIOD);
+ status = core_link_read_dpcd(link, DP_SET_POWER,
+ &dpcd_power_state, sizeof(dpcd_power_state));
+
+ /* Delay 1 ms if AUX CH is in power down state. Based on spec
+ * section 2.3.1.2, if AUX CH may be powered down due to
+ * write to DPCD 600h = 2. Sink AUX CH is monitoring differential
+ * signal and may need up to 1 ms before being able to reply.
+ */
+ if (status != DC_OK || dpcd_power_state == DP_SET_POWER_D3)
+ udelay(1000);
+
+ dpcd_set_source_specific_data(link);
+ /* Sink may need to configure internals based on vendor, so allow some
+ * time before proceeding with possibly vendor specific transactions
+ */
+ msleep(post_oui_delay);
+
+ for (i = 0; i < read_dpcd_retry_cnt; i++) {
+ status = core_link_read_dpcd(
+ link,
+ DP_DPCD_REV,
+ dpcd_data,
+ sizeof(dpcd_data));
+ if (status == DC_OK)
+ break;
+ }
+
+
+ if (status != DC_OK) {
+ dm_error("%s: Read receiver caps dpcd data failed.\n", __func__);
+ return false;
+ }
+
{
union training_aux_rd_interval aux_rd_interval;
--
2.25.1
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