ttm_fbdev_mmap() just doesn't work. It appears to work fine, mmap() returns success, but any attempt to actually access the mapping causes a SIGBUS.
We can just use drm_gem_prime_mmap() instead. Almost. We have to copy over the start offset from the ttm_buffer_object vm_node to the drm_gem_object vm_node so the offset math in drm_gem_prime_mmap() works correctly for us even though we use ttm to manage our objects.
Signed-off-by: Gerd Hoffmann kraxel@redhat.com --- drivers/gpu/drm/bochs/bochs_mm.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/bochs/bochs_mm.c b/drivers/gpu/drm/bochs/bochs_mm.c index 641a33f134..49463348a0 100644 --- a/drivers/gpu/drm/bochs/bochs_mm.c +++ b/drivers/gpu/drm/bochs/bochs_mm.c @@ -442,5 +442,6 @@ int bochs_gem_prime_mmap(struct drm_gem_object *obj, { struct bochs_bo *bo = gem_to_bochs_bo(obj);
- return ttm_fbdev_mmap(vma, &bo->bo); + bo->gem.vma_node.vm_node.start = bo->bo.vma_node.vm_node.start; + return drm_gem_prime_mmap(obj, vma); }