[PATCH] drm/amdgpu: Add kernel parameter to force no xgmi

[Alex Sierra]

By enabling this parameter, the system will be forced to use pcie
interface only for p2p transactions.

Signed-off-by: Alex Sierra <alex.sierra at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu.h        | 1 +
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 2 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c    | 9 +++++++++
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index ba65d4f2ab67..3645f00e9f61 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -188,6 +188,7 @@ extern int amdgpu_discovery;
 extern int amdgpu_mes;
 extern int amdgpu_noretry;
 extern int amdgpu_force_asic_type;
+extern int amdgpu_force_no_xgmi;
 #ifdef CONFIG_HSA_AMD
 extern int sched_policy;
 extern bool debug_evictions;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 1fe850e0a94d..0a5d97a84017 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -2257,7 +2257,7 @@ static int amdgpu_device_ip_init(struct amdgpu_device *adev)
 	if (r)
 		goto init_failed;
 
-	if (adev->gmc.xgmi.num_physical_nodes > 1)
+	if (!amdgpu_force_no_xgmi && adev->gmc.xgmi.num_physical_nodes > 1)
 		amdgpu_xgmi_add_device(adev);
 	amdgpu_amdkfd_device_init(adev);
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index 4b78ecfd35f7..22485067cf31 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -160,6 +160,7 @@ int amdgpu_force_asic_type = -1;
 int amdgpu_tmz = 0;
 int amdgpu_reset_method = -1; /* auto */
 int amdgpu_num_kcq = -1;
+int amdgpu_force_no_xgmi = 0;
 
 struct amdgpu_mgpu_info mgpu_info = {
 	.mutex = __MUTEX_INITIALIZER(mgpu_info.mutex),
@@ -522,6 +523,14 @@ module_param_named(ras_enable, amdgpu_ras_enable, int, 0444);
 MODULE_PARM_DESC(ras_mask, "Mask of RAS features to enable (default 0xffffffff), only valid when ras_enable == 1");
 module_param_named(ras_mask, amdgpu_ras_mask, uint, 0444);
 
+/**
+ * DOC: force_no_xgmi (uint)
+ * Forces not to use xgmi interface (0 = disable, 1 = enable).
+ * Default is 0 (disabled).
+ */
+MODULE_PARM_DESC(force_no_xgmi, "Force not to use xgmi interface");
+module_param_named(force_no_xgmi, amdgpu_force_no_xgmi, int, 0600);
+
 /**
  * DOC: si_support (int)
  * Set SI support driver. This parameter works after set config CONFIG_DRM_AMDGPU_SI. For SI asic, when radeon driver is enabled,
-- 
2.17.1