From 96e693ad78a0778efb5256684a2f3712298f3e18 Mon Sep 17 00:00:00 2001 From: Sonny Jiang Date: Tue, 28 Mar 2023 13:19:11 -0400 Subject: [PATCH] drm/amdgpu: Add a read after write DB_CTRL for vcn_v4_0_3 To make sure VCN DB_CTRL is delivered before doorbell write. Signed-off-by: Sonny Jiang Reviewed-by: Lijo Lazar Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/amdgpu/vcn_v4_0_3.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/gpu/drm/amd/amdgpu/vcn_v4_0_3.c b/drivers/gpu/drm/amd/amdgpu/vcn_v4_0_3.c index b0e28d6..9d0c3dc 100644 --- a/drivers/gpu/drm/amd/amdgpu/vcn_v4_0_3.c +++ b/drivers/gpu/drm/amd/amdgpu/vcn_v4_0_3.c @@ -195,6 +195,11 @@ static int vcn_v4_0_3_hw_init(void *handle) ring->doorbell_index << VCN_RB1_DB_CTRL__OFFSET__SHIFT | VCN_RB1_DB_CTRL__EN_MASK); + + /* Read DB_CTRL to flush the write DB_CTRL command. */ + RREG32_SOC15( + VCN, GET_INST(VCN, ring->me), + regVCN_RB1_DB_CTRL); } r = amdgpu_ring_test_helper(ring); -- 2.7.4