drm/amdgpu: improve MSI-X handling (v3)

Check the number of supported vectors and fall back to MSI if
we return or error or 0 MSI-X vectors.

v2: only allocate one vector.  We can't currently use more than
one anyway.

v3: install the irq on vector 0.

Tested-by: Tom St Denis <tom.stdenis@amd.com>
Reviewed-by: Shaoyun liu  <shaoyun.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c
index 50771b2757dc8a036915e9b232ce544d759385b0..6f3b03f6224f1a7640d9d3df0649dfc977af4b5e 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c
@@ -245,11 +245,19 @@ int amdgpu_irq_init(struct amdgpu_device *adev)
        adev->irq.msi_enabled = false;
 
        if (amdgpu_msi_ok(adev)) {
-               int nvec = pci_alloc_irq_vectors(adev->pdev, 1, pci_msix_vec_count(adev->pdev),
-                                       PCI_IRQ_MSI | PCI_IRQ_MSIX);
+               int nvec = pci_msix_vec_count(adev->pdev);
+               unsigned int flags;
+
+               if (nvec <= 0) {
+                       flags = PCI_IRQ_MSI;
+               } else {
+                       flags = PCI_IRQ_MSI | PCI_IRQ_MSIX;
+               }
+               /* we only need one vector */
+               nvec = pci_alloc_irq_vectors(adev->pdev, 1, 1, flags);
                if (nvec > 0) {
                        adev->irq.msi_enabled = true;
-                       dev_dbg(adev->dev, "amdgpu: using MSI.\n");
+                       dev_dbg(adev->dev, "amdgpu: using MSI/MSI-X.\n");
                }
        }
 
@@ -272,7 +280,8 @@ int amdgpu_irq_init(struct amdgpu_device *adev)
        INIT_WORK(&adev->irq.ih2_work, amdgpu_irq_handle_ih2);
 
        adev->irq.installed = true;
-       r = drm_irq_install(adev->ddev, adev->ddev->pdev->irq);
+       /* Use vector 0 for MSI-X */
+       r = drm_irq_install(adev->ddev, pci_irq_vector(adev->pdev, 0));
        if (r) {
                adev->irq.installed = false;
                if (!amdgpu_device_has_dc_support(adev))