[PATCHv2] drm/amdgpu: register a vga_switcheroo client for MacBooks with apple-gmux

[Orlando Chamberlain]

Commit 3840c5bcc245 ("drm/amdgpu: disentangle runtime pm and
vga_switcheroo") made amdgpu only register a vga_switcheroo client for
GPU's with PX, however AMD GPUs in dual gpu Apple Macbooks do need to
register, but don't have PX. Instead of AMD's PX, they use apple-gmux.

Use apple_gmux_detect() to identify these gpus, and
pci_is_thunderbolt_attached() to ensure eGPUs connected to Dual GPU
Macbooks don't register with vga_switcheroo.

Fixes: 3840c5bcc245 ("drm/amdgpu: disentangle runtime pm and vga_switcheroo")
Link: 
https://lore.kernel.org/amd-gfx/20230210044826.9834-10-orlandoch....@gmail.com/
Signed-off-by: Orlando Chamberlain <orlandoch....@gmail.com>
---
v1->v2: Use apple_gmux_detect()
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 2f28a8c02f64..ef8b996f0622 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -35,6 +35,7 @@
 #include <linux/devcoredump.h>
 #include <generated/utsrelease.h>
 #include <linux/pci-p2pdma.h>
+#include <linux/apple-gmux.h>
 
 #include <drm/drm_aperture.h>
 #include <drm/drm_atomic_helper.h>
@@ -3919,12 +3920,15 @@ int amdgpu_device_init(struct amdgpu_device *adev,
        if ((adev->pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA)
                vga_client_register(adev->pdev, amdgpu_device_vga_set_decode);
 
-       if (amdgpu_device_supports_px(ddev)) {
-               px = true;
+       px = amdgpu_device_supports_px(ddev);
+
+       if (px || (!pci_is_thunderbolt_attached(adev->pdev) &&
+                               apple_gmux_detect(NULL, NULL)))
                vga_switcheroo_register_client(adev->pdev,
                                               &amdgpu_switcheroo_ops, px);
+
+       if (px)
                vga_switcheroo_init_domain_pm_ops(adev->dev, 
&adev->vga_pm_domain);
-       }
 
        if (adev->gmc.xgmi.pending_reset)
                queue_delayed_work(system_wq, &mgpu_info.delayed_reset_work,
@@ -4029,6 +4033,7 @@ void amdgpu_device_fini_hw(struct amdgpu_device *adev)
 void amdgpu_device_fini_sw(struct amdgpu_device *adev)
 {
        int idx;
+       bool px;
 
        amdgpu_fence_driver_sw_fini(adev);
        amdgpu_device_ip_fini(adev);
@@ -4048,10 +4053,16 @@ void amdgpu_device_fini_sw(struct amdgpu_device *adev)
 
        kfree(adev->bios);
        adev->bios = NULL;
-       if (amdgpu_device_supports_px(adev_to_drm(adev))) {
+
+       px = amdgpu_device_supports_px(adev_to_drm(adev));
+
+       if (px || (!pci_is_thunderbolt_attached(adev->pdev) &&
+                               apple_gmux_detect(NULL, NULL)))
                vga_switcheroo_unregister_client(adev->pdev);
+
+       if (px)
                vga_switcheroo_fini_domain_pm_ops(adev->dev);
-       }
+
        if ((adev->pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA)
                vga_client_unregister(adev->pdev);
 
-- 
2.39.1