drm/amd/display: increase pstate wait timeout

For linux it takes longer than 40us so increasing it to
200us. Also added debug prints regarding the change

Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
index db774b3c3721becac2a80fef3989cc0338773766..012ba7c9ca8de5cf8b18260ded307a6a747cc8af 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
@@ -245,8 +245,13 @@ static void verify_allow_pstate_change_high(
 {
        /* pstate latency is ~20us so if we wait over 40us and pstate allow
         * still not asserted, we are probably stuck and going to hang
+        *
+        * TODO: Figure out why it takes ~100us on linux
+        * pstate takes around ~100us on linux. Unknown currently as to
+        * why it takes that long on linux
         */
-       static unsigned int pstate_wait_timeout_us = 40;
+       static unsigned int pstate_wait_timeout_us = 200;
+       static unsigned int pstate_wait_expected_timeout_us = 40;
        static unsigned int max_sampled_pstate_wait_us; /* data collection */
        static bool forced_pstate_allow; /* help with revert wa */
        static bool should_log_hw_state; /* prevent hw state log by default */
@@ -293,9 +298,15 @@ static void verify_allow_pstate_change_high(
        for (i = 0; i < pstate_wait_timeout_us; i++) {
                debug_data = REG_READ(DCHUBBUB_TEST_DEBUG_DATA);
 
-               if (debug_data & (1 << 30))
-                       return;
+               if (debug_data & (1 << 30)) {
+
+                       if (i > pstate_wait_expected_timeout_us)
+                               dm_logger_write(hws->ctx->logger, LOG_WARNING,
+                                               "pstate took longer than expected ~%dus",
+                                               i);
 
+                       return;
+               }
                if (max_sampled_pstate_wait_us < i)
                        max_sampled_pstate_wait_us = i;
 
@@ -314,6 +325,9 @@ static void verify_allow_pstate_change_high(
                dcn10_log_hw_state(hws->ctx->dc);
        }
 
+       dm_logger_write(hws->ctx->logger, LOG_WARNING,
+                       "pstate TEST_DEBUG_DATA: 0x%X",
+                       debug_data);
        BREAK_TO_DEBUGGER();
 }