On 6/29/22 01:42, Dmitry Osipenko wrote: > The code assumes that Tegra GEM is permanently vmapped, which is not > true for the scattered buffers. After converting Tegra video decoder > driver to V4L API, we're now getting a BUG_ON from dma-buf core on playing > video using libvdpau-tegra on T30+ because tegra_gem_prime_vmap() sets > vaddr to NULL. Older pre-V4L video decoder driver wasn't vmapping dma-bufs. > Fix it by actually vmapping the exported GEMs. > > Cc: [email protected] > Signed-off-by: Dmitry Osipenko <[email protected]> > --- > drivers/gpu/drm/tegra/gem.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c > index 7c7dd84e6db8..81991090adcc 100644 > --- a/drivers/gpu/drm/tegra/gem.c > +++ b/drivers/gpu/drm/tegra/gem.c > @@ -704,14 +704,23 @@ static int tegra_gem_prime_vmap(struct dma_buf *buf, > struct iosys_map *map) > { > struct drm_gem_object *gem = buf->priv; > struct tegra_bo *bo = to_tegra_bo(gem); > + void *vaddr; > > - iosys_map_set_vaddr(map, bo->vaddr); > + vaddr = tegra_bo_mmap(&bo->base); > + if (IS_ERR(vaddr)) > + return PTR_ERR(vaddr); > + > + iosys_map_set_vaddr(map, vaddr); > > return 0; > } > > static void tegra_gem_prime_vunmap(struct dma_buf *buf, struct iosys_map > *map) > { > + struct drm_gem_object *gem = buf->priv; > + struct tegra_bo *bo = to_tegra_bo(gem); > + > + tegra_bo_munmap(&bo->base, map->vaddr); > } > > static const struct dma_buf_ops tegra_gem_prime_dmabuf_ops = {
BTW, previously I only tested video dec on T30 using the grate-driver kernel that properly vmaps GEMs. That's why it wasn't caught earlier. -- Best regards, Dmitry
