drm/amd: Refactor `amdgpu_aspm` to be evaluated per device

Evaluating `pcie_aspm_enabled` as part of driver probe has the implication
that if one PCIe bridge with an AMD GPU connected doesn't support ASPM
then none of them do.  This is an invalid assumption as the PCIe core will
configure ASPM for individual PCIe bridges.

Create a new helper function that can be called by individual dGPUs to
react to the `amdgpu_aspm` module parameter without having negative results
for other dGPUs on the PCIe bus.

Suggested-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 25 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 5b772f2af6eb..0cfccea722f8 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -1318,6 +1318,31 @@ bool amdgpu_device_need_post(struct amdgpu_device *adev)
 	return true;
 }
 
+/**
+ * amdgpu_device_should_use_aspm - check if the device should program ASPM
+ *
+ * @adev: amdgpu_device pointer
+ *
+ * Confirm whether the module parameter and pcie bridge agree that ASPM should
+ * be set for this device.
+ *
+ * Returns true if it should be used or false if not.
+ */
+bool amdgpu_device_should_use_aspm(struct amdgpu_device *adev)
+{
+	switch (amdgpu_aspm) {
+	case -1:
+		break;
+	case 0:
+		return false;
+	case 1:
+		return true;
+	default:
+		return false;
+	}
+	return pcie_aspm_enabled(adev->pdev);
+}
+
 /* if we get transitioned to only one device, take VGA back */
 /**
  * amdgpu_device_vga_set_decode - enable/disable vga decode