[PATCH 24/37] drm/amd/display: Force flush after write to IPS driver signals

[Aurabindo Pillai]

From: Nicholas Kazlauskas <nicholas.kazlaus...@amd.com>

[Why]
It's possible that the write hasn't fully completed by the time we
send (and flush) a command to DMCUB to notify idle to request IPS2
exit.

[How]
Perform a readback of the volatile structure into dc_dmub_srv state.

Reviewed-by: Charlene Liu <charlene....@amd.com>
Acked-by: Aurabindo Pillai <aurabindo.pil...@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlaus...@amd.com>
Tested-by: Daniel Wheeler <daniel.whee...@amd.com>
---
 drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c | 2 ++
 drivers/gpu/drm/amd/display/dc/dc_dmub_srv.h | 1 +
 2 files changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c 
b/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c
index 3177000335b2..33d3307f5c1c 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c
+++ b/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c
@@ -1296,6 +1296,7 @@ static void dc_dmub_srv_notify_idle(const struct dc *dc, 
bool allow_idle)
                }
 
                ips_driver->signals = new_signals;
+               dc_dmub_srv->driver_signals = ips_driver->signals;
        }
 
        DC_LOG_IPS(
@@ -1339,6 +1340,7 @@ static void dc_dmub_srv_exit_low_power_state(const struct 
dc *dc)
                ips2_exit_count = ips_fw->ips2_exit_count;
 
                ips_driver->signals.all = 0;
+               dc_dmub_srv->driver_signals = ips_driver->signals;
 
                DC_LOG_IPS(
                        "%s (allow ips1=%d ips2=%d) (commit ips1=%d ips2=%d) 
(count rcg=%d ips1=%d ips2=%d)",
diff --git a/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.h 
b/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.h
index 72cc483e1556..3297c5b33265 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.h
+++ b/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.h
@@ -53,6 +53,7 @@ struct dc_dmub_srv {
        void *dm;
 
        int32_t idle_exit_counter;
+       union dmub_shared_state_ips_driver_signals driver_signals;
        bool idle_allowed;
        bool needs_idle_wake;
 };
-- 
2.44.0