drm/amd/display: Use HW lock mgr for PSR1 when only one eDP

[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: f245b400a223 ("Revert "drm/amd/display: Use HW lock mgr for PSR1"")
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3965
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>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit ed569e1279a3045d6b974226c814e071fa0193a6)
Cc: stable@vger.kernel.org

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 bf636b28e3e16eda6a007d9f69f1cd84717028a5..6e2fce329d73827ed423fefa24bbcd492ecb457d 100644 (file)
--- 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;
 }