[PATCH v2] drm/amdgpu: Fail fb creation from imported dma-bufs. (v2)

[raof at ubuntu.com]

From: Christopher James Halse Rogers <christopher.halse.rogers at canonical.com>

Any use of the framebuffer will migrate it to VRAM, which is not sensible for
an imported dma-buf.

v2: Use DRM_DEBUG_KMS to prevent userspace accidentally spamming dmesg.

Signed-off-by: Christopher James Halse Rogers <christopher.halse.rogers at canonical.com>
CC: amd-gfx at lists.freedesktop.org
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_display.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
index 39fc388f222a..2f2e9b5c8a6a 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
@@ -612,6 +612,12 @@ amdgpu_user_framebuffer_create(struct drm_device *dev,
 		return ERR_PTR(-ENOENT);
 	}
 
+	/* Handle is imported dma-buf, so cannot be migrated to VRAM for scanout */
+	if (obj->import_attach) {
+		DRM_DEBUG_KMS("Cannot create framebuffer from imported dma_buf\n");
+		return ERR_PTR(-EINVAL);
+	}
+
 	amdgpu_fb = kzalloc(sizeof(*amdgpu_fb), GFP_KERNEL);
 	if (amdgpu_fb == NULL) {
 		drm_gem_object_unreference_unlocked(obj);
-- 
2.11.0