drm/exynos: gem: Drop NONCONTIG flag for buffers allocated without IOMMU

When no IOMMU is available, all GEM buffers allocated by Exynos DRM driver
are contiguous, because of the underlying dma_alloc_attrs() function
provides only such buffers. In such case it makes no sense to keep
BO_NONCONTIG flag for the allocated GEM buffers. This allows to avoid
failures for buffer contiguity checks in the subsequent operations on GEM
objects.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
CC: stable@vger.kernel.org # v4.4+

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.c b/drivers/gpu/drm/exynos/exynos_drm_gem.c
index ef35bc23bb36..11cc01b47bc0 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_gem.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_gem.c
@@ -247,6 +247,15 @@ struct exynos_drm_gem *exynos_drm_gem_create(struct drm_device *dev,
         if (IS_ERR(exynos_gem))
                 return exynos_gem;
 
+        if (!is_drm_iommu_supported(dev) && (flags & EXYNOS_BO_NONCONTIG)) {
+                /*
+                 * when no IOMMU is available, all allocated buffers are
+                 * contiguous anyway, so drop EXYNOS_BO_NONCONTIG flag
+                 */
+                flags &= ~EXYNOS_BO_NONCONTIG;
+                DRM_WARN("Non-contiguous allocation is not supported without IOMMU, falling back to contiguous buffer\n");
+        }
+
         /* set memory type and cache attribute from user side. */
         exynos_gem->flags = flags;