From: Mario Limonciello mario.limonciello@amd.com

[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: stable@vger.kernel.org Reviewed-by: ChiaHsuan Chung chiahsuan.chung@amd.com Signed-off-by: Mario Limonciello mario.limonciello@amd.com Signed-off-by: Alex Hung alex.hung@amd.com --- 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; }