[PATCH] drm/amdgpu: keep mmhub clock gating being enabled during s2idle suspend

[Prike Liang]

Without MMHUB clock gating being enabled then MMHUB will not disconnect
from DF and will result in DF C-state entry can't be accessed during S2idle
suspend, and eventually s0ix entry will be blocked.

Signed-off-by: Prike Liang <Prike.Liang at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/mmhub_v2_3.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/mmhub_v2_3.c b/drivers/gpu/drm/amd/amdgpu/mmhub_v2_3.c
index 1957fb098c4d..cb3dca4834b4 100644
--- a/drivers/gpu/drm/amd/amdgpu/mmhub_v2_3.c
+++ b/drivers/gpu/drm/amd/amdgpu/mmhub_v2_3.c
@@ -568,6 +568,15 @@ static int mmhub_v2_3_set_clockgating(struct amdgpu_device *adev,
 {
 	if (amdgpu_sriov_vf(adev))
 		return 0;
+	/*
+	 * The issue mmhub can't disconnect from DF with clock gating being disabled
+	 * seems only observed at DF 3.0.3, with the same suspend sequence not seen
+	 * any issue on the DF 3.0.2 series platform.
+	 */
+	if (adev->in_s0ix) {
+		dev_dbg(adev->dev, "keep mmhub clock gating being enabled for s0ix\n");
+		return 0;
+	}
 
 	mmhub_v2_3_update_medium_grain_clock_gating(adev,
 				state == AMD_CG_STATE_GATE);
-- 
2.25.1