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@xxxxxxxxxxx>
CC: stable@xxxxxxxxxxxxxxx # v4.4+
---
This issue is there since commit 0519f9a12d011 ("drm/exynos: add iommu
support for exynos drm framework"), but this patch applies cleanly
only to v4.4+ kernel releases due changes in the surrounding code.
Changelog:
v2:
- added warning message when buffer flags are updadated (requested by Inki)
v1: https://patchwork.kernel.org/patch/10034919/
- initial version
---
drivers/gpu/drm/exynos/exynos_drm_gem.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.c b/drivers/gpu/drm/exynos/exynos_drm_gem.c
index 077de014d610..4400efe3974a 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;
--
2.14.2