[PATCH 4.4 060/134] drm/amdgpu: Fail fb creation from imported dma-bufs. (v2)

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

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


[ Upstream commit 1769152ac64b0b07583f696b621624df2ca4c840 ]

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.

Reviewed-by: Michel Dänzer <michel.daenzer at amd.com>
Reviewed-by: Christian König <christian.koenig at amd.com>
Signed-off-by: Christopher James Halse Rogers <christopher.halse.rogers at canonical.com>
CC: amd-gfx at lists.freedesktop.org
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
Signed-off-by: Sasha Levin <alexander.levin at microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_display.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
@@ -560,6 +560,12 @@ amdgpu_user_framebuffer_create(struct dr
 		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);