| Message ID | 20190204183858.8976-1-kraxel@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/bochs: fix bochs_gem_prime_mmap | expand |
On Mon, Feb 04, 2019 at 07:38:58PM +0100, Gerd Hoffmann wrote: > 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> Would be kinda neat if we could teach ttm to not have it's own vma node ... Anyway, lgtm. Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> > --- > 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); > } > -- > 2.9.3 >
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); }
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(-)