[PATCH 17/19] drm/amd/display: Allow Z8 for multiplane configurations on DCN35

[Alex Hung]

From: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>

[Why]
Power improvement over DCN314, but also addresses a functional issue
where plane_state remains uncleared on pipes that aren't actually
active.

[How]
Update the check to allow for zero streams to be treated as z8 allow.
Update the check to remove plane count on the active stream case.

Z8 will still be blocked based on stutter duration, which is likely to
be the case for most multi plane configurations.

Reviewed-by: Gabe Teeger <gabe.teeger at amd.com>
Reviewed-by: Charlene Liu <charlene.liu at amd.com>
Acked-by: Alex Hung <alex.hung at amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>
---
 drivers/gpu/drm/amd/display/dc/dml/dcn35/dcn35_fpu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dml/dcn35/dcn35_fpu.c b/drivers/gpu/drm/amd/display/dc/dml/dcn35/dcn35_fpu.c
index 475c4ec43c01..a85693caebd5 100644
--- a/drivers/gpu/drm/amd/display/dc/dml/dcn35/dcn35_fpu.c
+++ b/drivers/gpu/drm/amd/display/dc/dml/dcn35/dcn35_fpu.c
@@ -583,9 +583,9 @@ void dcn35_decide_zstate_support(struct dc *dc, struct dc_state *context)
 			plane_count++;
 	}
 
-	if (plane_count == 0) {
+	if (context->stream_count == 0 || plane_count == 0) {
 		support = DCN_ZSTATE_SUPPORT_ALLOW;
-	} else if (plane_count == 1 && context->stream_count == 1 && context->streams[0]->signal == SIGNAL_TYPE_EDP) {
+	} else if (context->stream_count == 1 && context->streams[0]->signal == SIGNAL_TYPE_EDP) {
 		struct dc_link *link = context->streams[0]->sink->link;
 		bool is_pwrseq0 = link && link->link_index == 0;
 		bool is_psr1 = link && link->psr_settings.psr_version == DC_PSR_VERSION_1 && !link->panel_config.psr.disable_psr;
-- 
2.34.1