From: Dmitry Osipenko <dig...@gmail.com>
commit 61b51fb51c01a519a249d28ec55c6513a13be5a3 upstream.
The allocated pages need to be invalidated in CPU caches. On ARM32 the
DMA_BIDIRECTIONAL flag only ensures that data is written-back to DRAM and
the data stays in CPU cache lines. While the DMA_FROM_DEVICE flag ensures
that the corresponding CPU cache lines are getting invalidated and nothing
more, that's exactly what is needed for a newly allocated pages.
This fixes randomly failing rendercheck tests on Tegra30 using the
Opentegra driver for tests that use small-sized pixmaps (10x10 and less,
i.e. 1-2 memory pages) because apparently CPU reads out stale data from
caches and/or that data is getting evicted to DRAM at the time of HW job
execution.
Fixes: bd43c9f0fa1f ("drm/tegra: gem: Map pages via the DMA API")
Cc: stable <sta...@vger.kernel.org>
Signed-off-by: Dmitry Osipenko <dig...@gmail.com>
Signed-off-by: Thierry Reding <tred...@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/gpu/drm/tegra/gem.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/gpu/drm/tegra/gem.c
+++ b/drivers/gpu/drm/tegra/gem.c
@@ -204,7 +204,7 @@ static void tegra_bo_free(struct drm_dev
{
if (bo->pages) {
dma_unmap_sg(drm->dev, bo->sgt->sgl, bo->sgt->nents,
- DMA_BIDIRECTIONAL);
+ DMA_FROM_DEVICE);
drm_gem_put_pages(&bo->gem, bo->pages, true, true);
sg_free_table(bo->sgt);
kfree(bo->sgt);
@@ -230,7 +230,7 @@ static int tegra_bo_get_pages(struct drm
}
err = dma_map_sg(drm->dev, bo->sgt->sgl, bo->sgt->nents,
- DMA_BIDIRECTIONAL);
+ DMA_FROM_DEVICE);
if (err == 0) {
err = -EFAULT;
goto free_sgt;
