[PATCH 08/16] drm/amd/display: Full exit out of IPS2 when all allow signals have been cleared

[Roman.Li at amd.com]

From: Leo Chen <leo.chen at amd.com>

[Why]
A race condition occurs between cursor movement and vertical interrupt control
thread from OS, with both threads trying to exit IPS2.
Vertical interrupt control thread clears the prev driver allow signal while not fully
finishing the IPS2 exit process.

[How]
We want to detect all the allow signals have been cleared before we perform the full exit.

Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>
Signed-off-by: Leo Chen <leo.chen at amd.com>
Signed-off-by: Roman Li <roman.li at amd.com>
---
 drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c    | 6 ++++--
 drivers/gpu/drm/amd/display/dmub/inc/dmub_cmd.h | 3 ++-
 2 files changed, 6 insertions(+), 3 deletions(-)

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 8486c144d81c..f0417ee6fcf8 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c
+++ b/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c
@@ -1295,6 +1295,8 @@ static void dc_dmub_srv_notify_idle(const struct dc *dc, bool allow_idle)
 
 		memset(&new_signals, 0, sizeof(new_signals));
 
+		new_signals.bits.allow_idle = 1; /* always set */
+
 		if (dc->config.disable_ips == DMUB_IPS_ENABLE ||
 		    dc->config.disable_ips == DMUB_IPS_DISABLE_DYNAMIC) {
 			new_signals.bits.allow_pg = 1;
@@ -1390,7 +1392,7 @@ static void dc_dmub_srv_exit_low_power_state(const struct dc *dc)
 		 */
 		dc_dmub_srv->needs_idle_wake = false;
 
-		if (prev_driver_signals.bits.allow_ips2 &&
+		if ((prev_driver_signals.bits.allow_ips2 || prev_driver_signals.all == 0) &&
 		    (!dc->debug.optimize_ips_handshake ||
 		     ips_fw->signals.bits.ips2_commit || !ips_fw->signals.bits.in_idle)) {
 			DC_LOG_IPS(
@@ -1451,7 +1453,7 @@ static void dc_dmub_srv_exit_low_power_state(const struct dc *dc)
 		}
 
 		dc_dmub_srv_notify_idle(dc, false);
-		if (prev_driver_signals.bits.allow_ips1) {
+		if (prev_driver_signals.bits.allow_ips1 || prev_driver_signals.all == 0) {
 			DC_LOG_IPS(
 				"wait for IPS1 commit clear (ips1_commit=%u ips2_commit=%u)",
 				ips_fw->signals.bits.ips1_commit,
diff --git a/drivers/gpu/drm/amd/display/dmub/inc/dmub_cmd.h b/drivers/gpu/drm/amd/display/dmub/inc/dmub_cmd.h
index f9e82c4f8deb..6edd3d34c7b5 100644
--- a/drivers/gpu/drm/amd/display/dmub/inc/dmub_cmd.h
+++ b/drivers/gpu/drm/amd/display/dmub/inc/dmub_cmd.h
@@ -752,7 +752,8 @@ union dmub_shared_state_ips_driver_signals {
 		uint32_t allow_ips1 : 1; /**< 1 is IPS1 is allowed */
 		uint32_t allow_ips2 : 1; /**< 1 is IPS1 is allowed */
 		uint32_t allow_z10 : 1; /**< 1 if Z10 is allowed */
-		uint32_t reserved_bits : 28; /**< Reversed bits */
+		uint32_t allow_idle : 1; /**< 1 if driver is allowing idle */
+		uint32_t reserved_bits : 27; /**< Reversed bits */
 	} bits;
 	uint32_t all;
 };
-- 
2.34.1