[PATCH] drm/radeon: avoid segfault on device open when accel is not working.

[j.glisse at gmail.com]

From: Jérôme Glisse <jglisse at redhat.com>

When accel is not working on device with virtual address space radeon
segfault because the ib buffer is NULL and trying to map it inside the
virtual address space trigger segfault. This patch only map the ib
buffer if accel is working.

Cc: <stable at vger.kernel.org>
Signed-off-by: Jérôme Glisse <jglisse at redhat.com>
---
 drivers/gpu/drm/radeon/radeon_kms.c | 55 +++++++++++++++++++------------------
 1 file changed, 29 insertions(+), 26 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_kms.c b/drivers/gpu/drm/radeon/radeon_kms.c
index 0cc47f1..eaaedba 100644
--- a/drivers/gpu/drm/radeon/radeon_kms.c
+++ b/drivers/gpu/drm/radeon/radeon_kms.c
@@ -577,28 +577,29 @@ int radeon_driver_open_kms(struct drm_device *dev, struct drm_file *file_priv)
 			return r;
 		}
 
-		r = radeon_bo_reserve(rdev->ring_tmp_bo.bo, false);
-		if (r) {
-			radeon_vm_fini(rdev, &fpriv->vm);
-			kfree(fpriv);
-			return r;
-		}
+		if (rdev->accel_working) {
+			r = radeon_bo_reserve(rdev->ring_tmp_bo.bo, false);
+			if (r) {
+				radeon_vm_fini(rdev, &fpriv->vm);
+				kfree(fpriv);
+				return r;
+			}
 
-		/* map the ib pool buffer read only into
-		 * virtual address space */
-		bo_va = radeon_vm_bo_add(rdev, &fpriv->vm,
-					 rdev->ring_tmp_bo.bo);
-		r = radeon_vm_bo_set_addr(rdev, bo_va, RADEON_VA_IB_OFFSET,
-					  RADEON_VM_PAGE_READABLE |
-					  RADEON_VM_PAGE_SNOOPED);
+			/* map the ib pool buffer read only into
+			 * virtual address space */
+			bo_va = radeon_vm_bo_add(rdev, &fpriv->vm,
+						 rdev->ring_tmp_bo.bo);
+			r = radeon_vm_bo_set_addr(rdev, bo_va, RADEON_VA_IB_OFFSET,
+						  RADEON_VM_PAGE_READABLE |
+						  RADEON_VM_PAGE_SNOOPED);
 
-		radeon_bo_unreserve(rdev->ring_tmp_bo.bo);
-		if (r) {
-			radeon_vm_fini(rdev, &fpriv->vm);
-			kfree(fpriv);
-			return r;
+			radeon_bo_unreserve(rdev->ring_tmp_bo.bo);
+			if (r) {
+				radeon_vm_fini(rdev, &fpriv->vm);
+				kfree(fpriv);
+				return r;
+			}
 		}
-
 		file_priv->driver_priv = fpriv;
 	}
 
@@ -626,13 +627,15 @@ void radeon_driver_postclose_kms(struct drm_device *dev,
 		struct radeon_bo_va *bo_va;
 		int r;
 
-		r = radeon_bo_reserve(rdev->ring_tmp_bo.bo, false);
-		if (!r) {
-			bo_va = radeon_vm_bo_find(&fpriv->vm,
-						  rdev->ring_tmp_bo.bo);
-			if (bo_va)
-				radeon_vm_bo_rmv(rdev, bo_va);
-			radeon_bo_unreserve(rdev->ring_tmp_bo.bo);
+		if (rdev->accel_working) {
+			r = radeon_bo_reserve(rdev->ring_tmp_bo.bo, false);
+			if (!r) {
+				bo_va = radeon_vm_bo_find(&fpriv->vm,
+							  rdev->ring_tmp_bo.bo);
+				if (bo_va)
+					radeon_vm_bo_rmv(rdev, bo_va);
+				radeon_bo_unreserve(rdev->ring_tmp_bo.bo);
+			}
 		}
 
 		radeon_vm_fini(rdev, &fpriv->vm);
-- 
1.9.0