On Tue, Jun 16, 2020 at 05:18:55PM +0300, Imre Deak wrote:
Atm, we clear the ACT sent flag in the sink's DPCD before updating the sink's payload table, along clearing the payload table updated flag. The sink is supposed to set this flag once it detects that the source has completed the ACT sequence (after detecting the 4 required ACT MTPH symbols sent by the source). As opposed to this 2 DELL monitors I have set the flag already along the payload table updated flag, which is not quite correct.
To be sure that the sink has detected the ACT MTPH symbols before continuing enabling the encoder, clear the ACT sent flag before enabling or disabling the transcoder VC payload allocation (which is what starts the ACT sequence).
Cc: Lyude Paul lyude@redhat.com Cc: Ville Syrjälä ville.syrjala@linux.intel.com Cc: dri-devel@lists.freedesktop.org Signed-off-by: Imre Deak imre.deak@intel.com
drivers/gpu/drm/drm_dp_mst_topology.c | 31 +++++++++++++++++++-- drivers/gpu/drm/i915/display/intel_dp_mst.c | 2 ++ include/drm/drm_dp_mst_helper.h | 2 ++ 3 files changed, 33 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index b2f5a84b4cfb..e3bf8c9c8267 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -4377,6 +4377,34 @@ void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr, } EXPORT_SYMBOL(drm_dp_mst_deallocate_vcpi);
+/**
- drm_dp_clear_payload_status() - Clears the payload table status flags
- @mgr: manager to use
- Clears the payload table ACT handled and table updated flags in the MST hub's
- DPCD. This function must be called before updating the payload table or
- starting the ACT sequence and waiting for the corresponding flags to get
- set by the hub.
- Returns:
- 0 if the flag got cleared successfully, otherwise a negative error code.
- */
+int drm_dp_clear_payload_status(struct drm_dp_mst_topology_mgr *mgr) +{
- int ret;
- ret = drm_dp_dpcd_writeb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS,
DP_PAYLOAD_ACT_HANDLED);- if (ret < 0) {
DRM_DEBUG_DRIVER("Can't clear the ACT sent flag (%d)\n", ret);return ret;- }
- WARN_ON(ret != 1);
- return 0;
+} +EXPORT_SYMBOL(drm_dp_clear_payload_status);
static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr, int id, struct drm_dp_payload *payload) { @@ -4384,8 +4412,7 @@ static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr, int ret; int retries = 0;
- drm_dp_dpcd_writeb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS,
DP_PAYLOAD_TABLE_UPDATED);
We used to clear DP_PAYLOAD_TABLE_UPDATED but now we clear DP_PAYLOAD_ACT_HANDLED ?
drm_dp_clear_payload_status(mgr);
payload_alloc[0] = id; payload_alloc[1] = payload->start_slot;
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c index 9308b5920780..3c4b0fb10d8b 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c @@ -323,6 +323,8 @@ static void clear_act_sent(struct intel_dp *intel_dp)
intel_de_write(i915, intel_dp->regs.dp_tp_status, DP_TP_STATUS_ACT_SENT);
- drm_dp_clear_payload_status(&intel_dp->mst_mgr);
}
static void wait_for_act_sent(struct intel_dp *intel_dp) diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h index 8b9eb4db3381..2facb87624bf 100644 --- a/include/drm/drm_dp_mst_helper.h +++ b/include/drm/drm_dp_mst_helper.h @@ -763,6 +763,8 @@ int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, int pbn);
+int drm_dp_clear_payload_status(struct drm_dp_mst_topology_mgr *mgr);
int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr);
-- 2.23.1