[PATCH v2] drm/amd/pm: Enable gfx DCS feature

[Lazar, Lijo]

[AMD Public Use]

Have some comments, please find inline <>

-----Original Message-----
From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of Kenneth Feng
Sent: Wednesday, January 27, 2021 1:47 PM
To: amd-gfx at lists.freedesktop.org
Cc: Zhou1, Tao <Tao.Zhou1 at amd.com>; Feng, Kenneth <Kenneth.Feng at amd.com>
Subject: [PATCH v2] drm/amd/pm: Enable gfx DCS feature

Background:
Gfx Duty Cycle Scaling(DCS) is applied on the small power limit skus.
When the current/power/temperature exceeds the limit with the heavy workload, the gfx core can be shut off and powered on back and forth.
The ON time and OFF time is determined by the firmware according to the accumulated power credits.
This feature is different from gfxoff.Gfxoff is applied in the idle case and DCS is applied in the case with heavey workload.There are two types of DCS:
Async DCS and Frame-aligned DCS.Frame-aligned DCS is applied on 3D fullscreen and VR workload.
Since we only supports Async DCS now,disalbe DCS when the 3D fullscreen or the VR workload type is chosen.

Verification:
The power is lowerer or the perf/watt is increased in the throttling case.
To be simplified, the entry/exit counter can be observed from the firmware.

Signed-off-by: Kenneth Feng <kenneth.feng at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c              |  8 ++++++--
 drivers/gpu/drm/amd/include/amd_shared.h             |  1 +
 .../gpu/drm/amd/pm/swsmu/smu11/sienna_cichlid_ppt.c  | 12 ++++++++++++
 3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index 82c2fa8a67cd..186bbe139bde 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -131,8 +131,12 @@ uint amdgpu_pg_mask = 0xffffffff;  uint amdgpu_sdma_phase_quantum = 32;  char *amdgpu_disable_cu = NULL;  char *amdgpu_virtual_display = NULL;
-/* OverDrive(bit 14) disabled by default*/ -uint amdgpu_pp_feature_mask = 0xffffbfff;
+
+/*
+ * OverDrive(bit 14) disabled by default
+ * GFX DCS(bit 19) disabled by default
+ */
+uint amdgpu_pp_feature_mask = 0xfff7bfff;

<> This  will cause a problem for other ASICS. This could be disabling feature bits which are no related.

 uint amdgpu_force_long_training;
 int amdgpu_job_hang_limit;
 int amdgpu_lbpw = -1;
diff --git a/drivers/gpu/drm/amd/include/amd_shared.h b/drivers/gpu/drm/amd/include/amd_shared.h
index 9676016a37ce..43ed6291b2b8 100644
--- a/drivers/gpu/drm/amd/include/amd_shared.h
+++ b/drivers/gpu/drm/amd/include/amd_shared.h
@@ -213,6 +213,7 @@ enum PP_FEATURE_MASK {
 	PP_ACG_MASK = 0x10000,
 	PP_STUTTER_MODE = 0x20000,
 	PP_AVFS_MASK = 0x40000,
+	PP_GFX_DCS_MASK = 0x80000,
 };
 
 enum DC_FEATURE_MASK {
diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu11/sienna_cichlid_ppt.c b/drivers/gpu/drm/amd/pm/swsmu/smu11/sienna_cichlid_ppt.c
index 24f3c96a5e5e..dffdcebc80e1 100644
--- a/drivers/gpu/drm/amd/pm/swsmu/smu11/sienna_cichlid_ppt.c
+++ b/drivers/gpu/drm/amd/pm/swsmu/smu11/sienna_cichlid_ppt.c
@@ -261,6 +261,9 @@ sienna_cichlid_get_allowed_feature_mask(struct smu_context *smu,
 		*(uint64_t *)feature_mask |= FEATURE_MASK(FEATURE_DPM_GFX_GPO_BIT);
 	}
 
+	if ((adev->pm.pp_feature & PP_GFX_DCS_MASK) && adev->asic_type > CHIP_SIENNA_CICHLID)
+		*(uint64_t *)feature_mask |= FEATURE_MASK(FEATURE_GFX_DCS_BIT);
+
 	if (adev->pm.pp_feature & PP_MCLK_DPM_MASK)
 		*(uint64_t *)feature_mask |= FEATURE_MASK(FEATURE_DPM_UCLK_BIT)
 					| FEATURE_MASK(FEATURE_MEM_VDDCI_SCALING_BIT)
@@ -1437,6 +1440,15 @@ static int sienna_cichlid_set_power_profile_mode(struct smu_context *smu, long *
 	smu_cmn_send_smc_msg_with_param(smu, SMU_MSG_SetWorkloadMask,
 				    1 << workload_type, NULL);
 
+	/* have to disable dcs if it's the 3D fullscreen or VR workload type */
+	if ((smu->adev->pm.pp_feature & PP_GFX_DCS_MASK) &&
+	    smu->adev->asic_type > CHIP_SIENNA_CICHLID) {
+		ret = smu_cmn_feature_set_enabled(smu, SMU_FEATURE_GFX_DCS_BIT, (workload_type ==
+			WORKLOAD_PPLIB_FULL_SCREEN_3D_BIT || workload_type == WORKLOAD_PPLIB_VR_BIT) ? 0 : 1);
+		if (ret)
+			return ret;
+	}

<> Is it guaranteed that power profile mode is set before running any 3D app? It seems optional and what happens if a 3D app is run without calling this?

Thanks,
Lijo

 	return ret;
 }
 
--
2.17.1

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