[PATCH] drm/amd:avoid null pointer dereference when dev is not bound

[Defang Bo]

[Why]
Similar to commit<0fa375e6>. If amdgpu_switcheroo_can_switch access
the drm_device when dev is not bound, a null pointer dereference can happen.

[How]
Add sanity checks to prevent it.

Signed-off-by: Defang Bo <bodefang@xxxxxxx>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 37da353..f70e528 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -1439,6 +1439,9 @@ static void amdgpu_switcheroo_set_state(struct pci_dev *pdev,
 static bool amdgpu_switcheroo_can_switch(struct pci_dev *pdev)
 {
 	struct drm_device *dev = pci_get_drvdata(pdev);
+
+	if (!dev)
+		return false;
 
 	/*
 	* FIXME: open_count is protected by drm_global_mutex but that would lead to
-- 
2.7.4