Hi All: I am investigating a S4 issue on CI which if DC is enabled . driver will be failed in the dpm funtions. (log as bellow), but if DC is disabled , everything goes well. I also found that if driver send PPSMC_MSG_MCLKDPM_FreezeLevel message to smc could cause smc hang when set power state during S4(freeze/thaw). So is it reasonable to disable mclk switch(maybe do not freeze/unfreeze are enough) during S4? appreciate to any suggustion. [ 43.852560] [drm:ci_dpm_set_power_state [amdgpu]] *ERROR* ci_freeze_sclk_mclk_dpm failed ............ [ 44.531935] [drm:ci_dpm_enable [amdgpu]] *ERROR* ci_notify_smc_display_change failed [ 44.591020] ata8: SATA link down (SStatus 0 SControl 300) [ 44.700953] [drm:gfx_v7_0_ring_test_ring [amdgpu]] *ERROR* amdgpu: ring 0 test failed (scratch(0xC040)=0xCAFEDEAD) [ 44.711961] [drm:amdgpu_resume [amdgpu]] *ERROR* resume of IP block <gfx_v7_0> failed -22 [ 44.720801] [drm:amdgpu_device_resume [amdgpu]] *ERROR* amdgpu_resume failed (-22). [ 44.729120] [drm:amdgpu_device_resume [amdgpu]] *ERROR* amdgpu_resume failed (-22). [ 44.898961] [drm:amdgpu_late_init [amdgpu]] *ERROR* late_init of IP block <amdgpu_powerplay> failed -22 [ 44.909008] dpm_run_callback(): pci_pm_thaw+0x0/0x90 returns -22 .................. amdgpu_pmops_poweroff [ 47.231267] e1000e: EEE TX LPI TIMER: 00000011 [ 47.316640] sd 4:0:0:0: [sda] Stopping disk [ 48.331698] [drm:vce_v2_0_firmware_loaded [amdgpu]] *ERROR* VCE not responding, trying to reset the ECPU!!! [ 49.354081] [drm:vce_v2_0_firmware_loaded [amdgpu]] *ERROR* VCE not responding, trying to reset the ECPU!!! [ 50.376450] [drm:vce_v2_0_firmware_loaded [amdgpu]] *ERROR* VCE not responding, trying to reset the ECPU!!! [ 51.398810] [drm:vce_v2_0_firmware_loaded [amdgpu]] *ERROR* VCE not responding, trying to reset the ECPU!!! [ 52.421144] [drm:vce_v2_0_firmware_loaded [amdgpu]] *ERROR* VCE not responding, trying to reset the ECPU!!! [ 53.443544] [drm:vce_v2_0_firmware_loaded [amdgpu]] *ERROR* VCE not responding, trying to reset the ECPU!!! [ 54.466875] [drm:vce_v2_0_firmware_loaded [amdgpu]] *ERROR* VCE not responding, trying to reset the ECPU!!! [ 55.489797] [drm:vce_v2_0_firmware_loaded [amdgpu]] *ERROR* VCE not responding, trying to reset the ECPU!!! [ 56.512146] [drm:vce_v2_0_firmware_loaded [amdgpu]] *ERROR* VCE not responding, trying to reset the ECPU!!! [ 57.534470] [drm:vce_v2_0_firmware_loaded [amdgpu]] *ERROR* VCE not responding, trying to reset the ECPU!!! [ 57.704577] PM: hibernate of devices complete after 10574.229 msecs [ 57.711298] PM: late hibernate of devices complete after 0.457 msecs Thanks JimQu