diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index b425ec00817c4..988b1c947aefc 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -1193,24 +1193,38 @@ static void mmhub_read_system_context(struct amdgpu_device *adev, struct dc_phy_
 
 	memset(pa_config, 0, sizeof(*pa_config));
 
-	logical_addr_low  = min(adev->gmc.fb_start, adev->gmc.agp_start) >> 18;
-	pt_base = amdgpu_gmc_pd_addr(adev->gart.bo);
-
-	if (adev->apu_flags & AMD_APU_IS_RAVEN2)
-		/*
-		 * Raven2 has a HW issue that it is unable to use the vram which
-		 * is out of MC_VM_SYSTEM_APERTURE_HIGH_ADDR. So here is the
-		 * workaround that increase system aperture high address (add 1)
-		 * to get rid of the VM fault and hardware hang.
-		 */
-		logical_addr_high = max((adev->gmc.fb_end >> 18) + 0x1, adev->gmc.agp_end >> 18);
-	else
-		logical_addr_high = max(adev->gmc.fb_end, adev->gmc.agp_end) >> 18;
-
 	agp_base = 0;
 	agp_bot = adev->gmc.agp_start >> 24;
 	agp_top = adev->gmc.agp_end >> 24;
 
+	/* AGP aperture is disabled */
+	if (agp_bot == agp_top) {
+		logical_addr_low  = adev->gmc.vram_start >> 18;
+		if (adev->apu_flags & AMD_APU_IS_RAVEN2)
+			/*
+			 * Raven2 has a HW issue that it is unable to use the vram which
+			 * is out of MC_VM_SYSTEM_APERTURE_HIGH_ADDR. So here is the
+			 * workaround that increase system aperture high address (add 1)
+			 * to get rid of the VM fault and hardware hang.
+			 */
+			logical_addr_high = (adev->gmc.fb_end >> 18) + 0x1;
+		else
+			logical_addr_high = adev->gmc.vram_end >> 18;
+	} else {
+		logical_addr_low  = min(adev->gmc.fb_start, adev->gmc.agp_start) >> 18;
+		if (adev->apu_flags & AMD_APU_IS_RAVEN2)
+			/*
+			 * Raven2 has a HW issue that it is unable to use the vram which
+			 * is out of MC_VM_SYSTEM_APERTURE_HIGH_ADDR. So here is the
+			 * workaround that increase system aperture high address (add 1)
+			 * to get rid of the VM fault and hardware hang.
+			 */
+			logical_addr_high = max((adev->gmc.fb_end >> 18) + 0x1, adev->gmc.agp_end >> 18);
+		else
+			logical_addr_high = max(adev->gmc.fb_end, adev->gmc.agp_end) >> 18;
+	}
+
+	pt_base = amdgpu_gmc_pd_addr(adev->gart.bo);
 
 	page_table_start.high_part = (u32)(adev->gmc.gart_start >> 44) & 0xF;
 	page_table_start.low_part = (u32)(adev->gmc.gart_start >> 12);