Re: [PATCH] drm/amdgpu: Adjust logic in amdgpu_device_partner_bandwidth()

[Christian König]

Am 16.05.24 um 17:05 schrieb Alex Deucher:

Use current speed/width on devices which don't support
dynamic PCIe switching.

Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3289
Signed-off-by: Alex Deucher <alexander.deuc...@amd.com>

Acked-by: Christian König <christian.koe...@amd.com>

---
  drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 19 ++++++++++++-------
  1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index e72e774d17e6a..f0011dac589d2 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -5946,13 +5946,18 @@ static void amdgpu_device_partner_bandwidth(struct 
amdgpu_device *adev,
        *speed = PCI_SPEED_UNKNOWN;
        *width = PCIE_LNK_WIDTH_UNKNOWN;

- while ((parent = pci_upstream_bridge(parent))) {

-               /* skip upstream/downstream switches internal to dGPU*/
-               if (parent->vendor == PCI_VENDOR_ID_ATI)
-                       continue;
-               *speed = pcie_get_speed_cap(parent);
-               *width = pcie_get_width_cap(parent);
-               break;
+       if (amdgpu_device_pcie_dynamic_switching_supported(adev)) {
+               while ((parent = pci_upstream_bridge(parent))) {
+                       /* skip upstream/downstream switches internal to dGPU*/
+                       if (parent->vendor == PCI_VENDOR_ID_ATI)
+                               continue;
+                       *speed = pcie_get_speed_cap(parent);
+                       *width = pcie_get_width_cap(parent);
+                       break;
+               }
+       } else {
+               /* use the current speeds rather than max if switching is not 
supported */
+               pcie_bandwidth_available(adev->pdev, NULL, speed, width);
        }
  }