From: Mario Limonciello <[email protected]>

[WHY]
DMUB locking is important to make sure that registers aren't accessed
while in PSR.  Previously it was enabled but caused a deadlock in
situations with multiple eDP panels.

[HOW]
Detect if multiple eDP panels are in use to decide whether to use
lock. Refactor the function so that the first check is for PSR-SU
and then replay is in use to prevent having to look up number
of eDP panels for those configurations.

Fixes: 06fbedfaf1a9 ("Revert "drm/amd/display: Use HW lock mgr for PSR1"")
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3965
Cc: [email protected]
Reviewed-by: ChiaHsuan Chung <[email protected]>
Signed-off-by: Mario Limonciello <[email protected]>
Signed-off-by: Alex Hung <[email protected]>
---
 drivers/gpu/drm/amd/display/dc/dce/dmub_hw_lock_mgr.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dce/dmub_hw_lock_mgr.c 
b/drivers/gpu/drm/amd/display/dc/dce/dmub_hw_lock_mgr.c
index bf636b28e3e1..6e2fce329d73 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dmub_hw_lock_mgr.c
+++ b/drivers/gpu/drm/amd/display/dc/dce/dmub_hw_lock_mgr.c
@@ -69,5 +69,16 @@ bool should_use_dmub_lock(struct dc_link *link)
        if (link->replay_settings.replay_feature_enabled)
                return true;
 
+       /* only use HW lock for PSR1 on single eDP */
+       if (link->psr_settings.psr_version == DC_PSR_VERSION_1) {
+               struct dc_link *edp_links[MAX_NUM_EDP];
+               int edp_num;
+
+               dc_get_edp_links(link->dc, edp_links, &edp_num);
+
+               if (edp_num == 1)
+                       return true;
+       }
+
        return false;
 }
-- 
2.43.0

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